I can certainly see how the iPad 3 is good enough for many people, but I personally can't stand it. Apps and system animations that are butter-smooth on my iPhone 5 stutter like crazy on my iPad 3 (restored as new, iOS 7.0.4). As such, I'm probably going to give it to my mother and get the iPad Air. Some people just don't care about that kind of thing as much as I do, and if they don't mind the extra weight, the iPad 3 is fine.
That's why I stayed on iOS 5.1.1 and did not upgrade to iOS 7. My iPad 2 runs it ok but it sputters with some of the animations. Hopefully they'll refine things with iOS 7.1 and smooth out the experience like it was prior to iOS 7.