I bought a Retina Mini when they were released, as I thought it was what I wanted.
But what I found was that while Apple's own applications worked well at that screen size, a large number of apps were simply too small on that display to use comfortably.
After relatively short amounts of time using the Mini, I was starting to notice eyestrain--something which had not been a problem with my iPad 3.
It was, however, a problem for me with the iPad 2 due to its low resolution.
While high resolution, I really couldn't get past the terrible color quality of the Retina Mini's display after being used to the iPad 3 for a year either.
If you went from an iPad 1, 2, or the original Mini, I'm sure you wouldn't notice, but after the iPad 3 it was a real problem for me.
I have actually been without an iPad for the last six months, as I just didn't think they were what I needed any more.
While the app selection is great, they are very limited in a number of ways compared to Microsoft's Surface tablets for example: no multitasking, very limited media support, limited connectivity etc.
But in the end, it turns out that despite their limitations, the iPad is still the best tablet device overall, in my opinion, and I just recently picked up an iPad Air.
Compared to all the other tablets I have tried, everything just feels
right on that display. The color reproduction is great, and text is always at a comfortable size to read.
With the Mini, I was always having to bring the screen just that bit closer, or zoom in on web pages for things to be comfortable.
I often found myself using the Mini as a landscape device rather than a portrait device when browsing the web.
It makes sense, I suppose--
the Mini's screen height is close to the Air's screen width.
I can use the iPad Air for hours without my eyes feeling strained, and I mostly use it vertically--which is what I prefer with a tablet.
16:9 devices like the Surface were practically unusable vertically to me--I'm amazed that Apple seem to be the only company sticking with the 4:3 aspect ratio for tablets.
I even prefer the 4:3 ratio for video as well. Most of the content I seem to watch ends up either being 4:3 television, or 21:9 films.
Almost nothing I watch is 16:9, so the argument that content fills the screen doesn't hold any weight for me.
Films are going to be letterboxed no matter what tablet you use, and 4:3 content looks very small on a 16:9 display.
If your main use for the iPad is actually reading
books, then I understand why you might prefer the Mini.
It's lighter, the color issues don't matter, and you can size the text to whatever you find comfortable.
But I don't just read books on my iPad--and I would recommend a Kindle if you're buying something solely for reading books--I am often reading manuals or technical papers on the device, which were just too small on the Mini.
Every time I pick it up, it surprises me how much lighter and better put together the Air is compared to previous iPads.
If you are basing your decision to get a Mini on your experience with one of the older iPads, I would suggest trying out the Air first. Even compared to an iPad 2 it is very noticeably lighter.
I'm still not 100% sold on the thinner bezels, but that will affect all iPads going forward.
While it's perfectly comfortable to hold at the edges, I still preferred having a wider area to rest my thumbs on.