People keep asking me if I actually have tried the ip4 when I say the retina display is overhyped and well marketed. I don't own one, but I sat in an Apple store with my 3gs next to an ip4 and browsed the internet and ran as many apps as I could.
I gotta tell you, I didn't see a marked difference. Yes it was definitely sharper, and yes when I looked back to the 3gs it looked slightly fuzzy/blurry for a couple of seconds until my eyes adjusted, but I'm just not seeing the 2nd coming of Jesus here at all. Compound that with my ipad, which doesn't look blurry/fuzzy in the least, partly because of its higher resolution than the ip4, it's just a non issue for me.
The bottom line is that you are still looking at a tiny lower resolution screen, no matter how sharp stuff is I'm not going to spend all day browsing full internet sites squinting my eyes and constantly panning and zooming. Would I like the retina display on my ipad? Sure. But only if it was "free", as I don't see it would make very much a difference on using it.