At first, I was really enjoying the mini, and the screen resolution didnt bother me one bit. However, lately, I've been using it with low brightness, and the non-retina is really starting to irk me, especially with web surfing.
+1
Loved the mini size and it was fantastic for watching Netflix. But reading web pages was absolutely brutal. You had to zoom in on every page to read the text because in the unzoomed state the text was so small and pixelated..
Some people say that using the mini in portrait mode helps alleviate the poor text/web experience, I saw that advice after I had returned my mini, so can't comment as to the effectiveness of portrait mode browsing.
Am back to the ipad 3 and couldn't be happier. The text on web pages is super sharp and you don't need to zoom in to read anything.
Do miss the weight of the mini but reading/typing this on the ipad3 is just amazingly better.
Full disclosure, am in my low 40s so perhaps my eyesight is more sensitive than someone younger.
Best of luck in your decision.