Just wanted to chime in, as we've got all the iPad and iPhone models in the household. Here are my impressions/thoughts:
iPad Pro
Impressive spec-wise, but you know what it became after 2 weeks of new toy buzz wore off? The new coffee table magazine! Gorgeous screen, awesome to read with the news app (pro tip for international users, set it up as a new device with US region to get the news app to load up, still works perfectly with your AppleID, etc) and magazine subscriptions etc but in our experience totally unwieldy and awkward to actually use "like an iPad" meaning holding it in your hands, using the touch screen, typing (thumb typing all but impossible), chatting, texting, playing games, taking it with you in your computer bag to work on your commute (bigger footprint than my laptop, would need to buy a larger briefcase to accomodate it!) I can totally see it being great for artists, laptop relacement pioneers (if they get the smart keyboard accessory, which is not available outside the US) or those that only use it with it lying prone on a table, or propped up on its smart cover to watch movies or TV shows. In gaining its large screen, monster CPU, and great speakers, it seems to have lost the essence, or magic, of what made an iPad special, fun, and personal. The Apple Pencil is pretty cool, but not being an artist, it doesn't seem that big a deal, and kind of gimicky after a few minutes of doodling...I mean any old stylus will do for the other two iPad models for productivity note taking apps and the like.
iPad Air 2
Wife's preferred device. She feels the Mini 4 is too small for her. Her iPad doesn't leave the house, she likes to use it in the bed, on the couch, etc - She is an elementary school teacher, she checks her email, researches lesson plans and ideas, does her banking, shops, social media, edits photos taken on her 6+. She doesn't own a personal laptop anymore, just has the 7lb Windows brick her school provides her with. It is a really solid device. Can't say anything bad about it - its an iPad, probably as close to what the original vision for the product was as can be.
iPad Mini 4
My preferred device. Goes everywhere with me. Serves as my primary personal computer. Goes with me on the commute - read the entire Wheel of Time series on it (and its Mini predecessors), keep up to date on all the Star Wars comics (yes I am a complete nerd), all my personal finances, email and calendar on the go, used in board rooms to hand around during presentations, texting, Skype/FaceTime video conferencing (have not once used the camera on my MB or MBA for this purpose, iPad Mini is always the device I reach for, ahead of my iPhone as well) Photo and Video editing, gaming (Baldur's Gates, Oceanhorn, Final Fantasies, Football Manager Touch, etc) Twitter, Facebook... I just prefer its size and portability over the Air 2 - for me personally, this is the size the iPad should have been in the first place - thumb typing is perfect, the PPI is tight, icons are essentially the same size as the iPhone 6, nothing looks blown up, and now that it is on par feature-wise as well as on a display quality level and user experience performance parity (Haven't noticed any stuttering, slow downs, or constant memory dumps since upgrading from the Mini 3, where all of those things started to become an issue with iOS 9) there is no device with me more except my iPhone 6. My phone doesn't have all that much on it as a result. Its main function is my camera and video camera - but all the editing of those is done elsewhere - either the Mini 4 or on the home media server and home movie editing workhorse, the quadcore i7 Mac Mini.
iPhone 6+ & 6
Wife's preferred screen size is the 6+. She just likes it better, doesn't use it any differently than she did her regular 6. She's a phone-in-purse-or-jacket person. She has one of those Incipio cases where she can put her DL and CC in a little flip up piece on the back. She LOVES that. She does most of her texting on it and of course all her photography. I had it first. We swapped phones. I am a phone in front pants/jeans pocket person. After the initial neato factor wore off, it just started to irritate me. It wasn't as good as the iPad Mini for anything - After trying it out for a couple of weeks, I never used it for anything more than I had my iPhone 5 before it. Its bulk did not fit the role it played in my device line-up. Regular 6 was perfect for me. Quick email shots or texts between or during meetings, check calendar walking down the hallway or in line for a cup of coffee, etc. In a pinch can do what I need to do if iPad Mini or MB is not there (still have DropBox, Office, Numbers, Pages, Keynote, etc) but it still usually only comes out of my pocket if I want to capture a moment with the camera or am actually talking on the phone or texting.
Now I fully understand that this is all totally 100% subjective, and I am not right and you are not wrong, this is just my experience with the stuff!
One thing I will say, is that I would never have written this post on the iPad Pro, as I would have had to sit up in bed and lay it down on my lap to do so...holding it in your hand(s) and typing with it is not pleasant at all...although I do like the keyboard layout it got - wish I could enable that on the Mini, even though it would mean smaller keys, I could easily deal with that!
On a final note, I just want to address that I don't get the whole spec-wars thing a lot of posters are going on about. I mean it is really about the user experience. Who cares how much faster or not the A9 is than the A8X or how the iPad Pro must be the best because...A9X. Granted, I'm not running research institute grade medical modeling apps on my devices, and tend to not be a tab-whore when web-browsing, but split screen multitasking using all the native apps, plus Office, Numbers, Keynote, Pages, etc on all the latest iPad models is pretty much indistinguishable from one another preformance wise (yes, you get two full portait mode apps in landscape on the Pro, I get and appreciate that fact). I'm used to seeing these kind of arguments made on Windows and Android devices when comparing to Macs and iDevices. Seeing them between Apple devces is a bit weird to say the least and a bit misplaced and lot "you just don't get it, do you?" IMHO. Accepted that the iPad Mini 3 was a let down in this area, the current line-up of iPads and iPhones is pretty damn good, its hard to criticise too much. I don't care what the benchmarks say, as long as my user experience is really good, my games don't skip frames, and there are no appreciable load times to start up or switch between apps, that is what matters. I don't care whether there is 2GB or 4GB of RAM either as long as I don't get tab reloads and memory dumps all the time. That said, they should keep the Mini on par with the Air going forward. Fully expect to see the Air 3 get the A9X and the Mini 5 to get the A9 come the fall, with a new Pro 2 getting an A10X.
Ok, long enough! Feel free to rip it all apart!
iPad Pro
Impressive spec-wise, but you know what it became after 2 weeks of new toy buzz wore off? The new coffee table magazine! Gorgeous screen, awesome to read with the news app (pro tip for international users, set it up as a new device with US region to get the news app to load up, still works perfectly with your AppleID, etc) and magazine subscriptions etc but in our experience totally unwieldy and awkward to actually use "like an iPad" meaning holding it in your hands, using the touch screen, typing (thumb typing all but impossible), chatting, texting, playing games, taking it with you in your computer bag to work on your commute (bigger footprint than my laptop, would need to buy a larger briefcase to accomodate it!) I can totally see it being great for artists, laptop relacement pioneers (if they get the smart keyboard accessory, which is not available outside the US) or those that only use it with it lying prone on a table, or propped up on its smart cover to watch movies or TV shows. In gaining its large screen, monster CPU, and great speakers, it seems to have lost the essence, or magic, of what made an iPad special, fun, and personal. The Apple Pencil is pretty cool, but not being an artist, it doesn't seem that big a deal, and kind of gimicky after a few minutes of doodling...I mean any old stylus will do for the other two iPad models for productivity note taking apps and the like.
iPad Air 2
Wife's preferred device. She feels the Mini 4 is too small for her. Her iPad doesn't leave the house, she likes to use it in the bed, on the couch, etc - She is an elementary school teacher, she checks her email, researches lesson plans and ideas, does her banking, shops, social media, edits photos taken on her 6+. She doesn't own a personal laptop anymore, just has the 7lb Windows brick her school provides her with. It is a really solid device. Can't say anything bad about it - its an iPad, probably as close to what the original vision for the product was as can be.
iPad Mini 4
My preferred device. Goes everywhere with me. Serves as my primary personal computer. Goes with me on the commute - read the entire Wheel of Time series on it (and its Mini predecessors), keep up to date on all the Star Wars comics (yes I am a complete nerd), all my personal finances, email and calendar on the go, used in board rooms to hand around during presentations, texting, Skype/FaceTime video conferencing (have not once used the camera on my MB or MBA for this purpose, iPad Mini is always the device I reach for, ahead of my iPhone as well) Photo and Video editing, gaming (Baldur's Gates, Oceanhorn, Final Fantasies, Football Manager Touch, etc) Twitter, Facebook... I just prefer its size and portability over the Air 2 - for me personally, this is the size the iPad should have been in the first place - thumb typing is perfect, the PPI is tight, icons are essentially the same size as the iPhone 6, nothing looks blown up, and now that it is on par feature-wise as well as on a display quality level and user experience performance parity (Haven't noticed any stuttering, slow downs, or constant memory dumps since upgrading from the Mini 3, where all of those things started to become an issue with iOS 9) there is no device with me more except my iPhone 6. My phone doesn't have all that much on it as a result. Its main function is my camera and video camera - but all the editing of those is done elsewhere - either the Mini 4 or on the home media server and home movie editing workhorse, the quadcore i7 Mac Mini.
iPhone 6+ & 6
Wife's preferred screen size is the 6+. She just likes it better, doesn't use it any differently than she did her regular 6. She's a phone-in-purse-or-jacket person. She has one of those Incipio cases where she can put her DL and CC in a little flip up piece on the back. She LOVES that. She does most of her texting on it and of course all her photography. I had it first. We swapped phones. I am a phone in front pants/jeans pocket person. After the initial neato factor wore off, it just started to irritate me. It wasn't as good as the iPad Mini for anything - After trying it out for a couple of weeks, I never used it for anything more than I had my iPhone 5 before it. Its bulk did not fit the role it played in my device line-up. Regular 6 was perfect for me. Quick email shots or texts between or during meetings, check calendar walking down the hallway or in line for a cup of coffee, etc. In a pinch can do what I need to do if iPad Mini or MB is not there (still have DropBox, Office, Numbers, Pages, Keynote, etc) but it still usually only comes out of my pocket if I want to capture a moment with the camera or am actually talking on the phone or texting.
Now I fully understand that this is all totally 100% subjective, and I am not right and you are not wrong, this is just my experience with the stuff!
One thing I will say, is that I would never have written this post on the iPad Pro, as I would have had to sit up in bed and lay it down on my lap to do so...holding it in your hand(s) and typing with it is not pleasant at all...although I do like the keyboard layout it got - wish I could enable that on the Mini, even though it would mean smaller keys, I could easily deal with that!
On a final note, I just want to address that I don't get the whole spec-wars thing a lot of posters are going on about. I mean it is really about the user experience. Who cares how much faster or not the A9 is than the A8X or how the iPad Pro must be the best because...A9X. Granted, I'm not running research institute grade medical modeling apps on my devices, and tend to not be a tab-whore when web-browsing, but split screen multitasking using all the native apps, plus Office, Numbers, Keynote, Pages, etc on all the latest iPad models is pretty much indistinguishable from one another preformance wise (yes, you get two full portait mode apps in landscape on the Pro, I get and appreciate that fact). I'm used to seeing these kind of arguments made on Windows and Android devices when comparing to Macs and iDevices. Seeing them between Apple devces is a bit weird to say the least and a bit misplaced and lot "you just don't get it, do you?" IMHO. Accepted that the iPad Mini 3 was a let down in this area, the current line-up of iPads and iPhones is pretty damn good, its hard to criticise too much. I don't care what the benchmarks say, as long as my user experience is really good, my games don't skip frames, and there are no appreciable load times to start up or switch between apps, that is what matters. I don't care whether there is 2GB or 4GB of RAM either as long as I don't get tab reloads and memory dumps all the time. That said, they should keep the Mini on par with the Air going forward. Fully expect to see the Air 3 get the A9X and the Mini 5 to get the A9 come the fall, with a new Pro 2 getting an A10X.
Ok, long enough! Feel free to rip it all apart!