Overall, I'm pleased with my choice of the 6 Plus. The screen of the phone is fantastic, and it feels good in the hand. I could see how it wouldn't be for everyone, but I have big hands, and I don't wear tight clothes so it's fine in my pocket.
My thoughts are below.
While the phone feels, looks, and performs fantastic, I'm disappointed with iOS 8. I've been using Android for the last 6 months, and while iOS 8 is an improvement over 7, it feels quite boring in comparison to Android. The home screen is the same, boring jumble of icons that it has always been. The widget implementation in the "Today" screen is a joke, in my opinion. I am really missing the ability to open the phone and instantly see a summary of my meetings and tasks for the day, and the ability to hide apps that are often unused but are necessary to have installed in the App Drawer. Sure, I can unlock the phone and then pull down the today screen but it just isn't the same. Being able to swipe up and have Google Now provide flight cards, weather, upcoming TV shows I watch, and other suggestions was awesome; it also would let me know in the notification center if there was an alert for anything that I had reminders set for, and how long it would currently take to drive to work or home. Apple should seriously look into some sort of similar system, and provide a better widget setup. Sure, not everyone wants widgets. Some say they're pointless. I find them incredibly useful after using them for months, and it would be nice to have the option to use them on the main screens; if you don't want to use them - just don't.
However, Android Apps don't feel as polished as the ones for iOS. Granted, the current iOS apps all look like hell since they're not optimized for the 6 or 6 Plus, but that will change. The lock screen notifications on iOS are far superior. The pull down notification center in iOS is horrible in comparison.
There will always be a group of fanboys that bash the competition. I work in IT, and I try to see the best in all platforms. Every piece of hardware and OS has positives and negatives. I think Apple has started to open up a bit more and I'm encouraged by that. I just think they need to take that a bit further and allow additional customization of the OS. Until you've used Android, don't bash it. I don't mean "I used a friends phone for a few minutes and OMG it sucked compared to Apple" - I mean, really try and use it for a few months. It continues to grow and improve with every release. The 6 Plus was enough to bring me back, as well as a few other folks I know. Who knows what hardware will be released on the "dark side" 6 months from now, though. Maybe I will stay, maybe I'll switch back. Who knows.
Right now, I just can't get over how nice the 6 Plus looks and feels
tldr; Love the phone. Dislike the OS.