I use both iPads regularly. I find myself taking the iPad mini with me where ever I go (both on trips and just in my work bag), while I tend to leave the regular iPad at home.
A retina iPad mini may tempt me to only use that device, though I do still like the larger screen when I’m sitting at home on the couch. My main issue with that device is the weight, and that’s supposedly being remedied this time around.
I have a Kindle Paperwhite as well, though I only tend to use that while reading before going to bed (or on a sunny beach).
I know I’m a device outlier — most folks will only get and use one of these devices. My guess is that a retina iPad mini will be the right call for most people. But we’ll see next week!
I do use the Kindle Paperwhite on nearly a nightly basis. After staring a backlit screens all day long, I still find the Paperwhite nice on my eyes before I go to sleep. I’m also about to take off to a beach for the long weekend and it’s definitely great in that setting.
Overall, the Kindle inventory and lending library aspect seems better than iBooks, but I actually like the look of iBooks better. Kindle has been getting better at removing some of the cruft in the reading experience, but there’s still more to go.
Long story short: I don’t really use the iPad mini for reading books, but I use it all the time for reading the internet. I use the Kindle Paperwhite for reading books. We’ll see if a retina iPad mini changes that equation.
Simple: it will be the same resolution as the third and fourth generation iPads — the retina ones. They’ll simply double the resolution of the iPad mini, not target the iPhone 5.