Well, if you want even more information on iPad specs, check the Apple Comparison Chart - the r-iPad has the new A6X chip (vs. the older A5 on the mini), which offers 4x the pixel density of the iPad2 & iPad Mini (of course, the pixels/inch is slightly higher on the latter due to the smaller screen) - the retina display on my new MacBook Pro is amazingly sharp -
For the record ipad mini has higher ppi density than the ipad 2, so expect the display quality on the ipad mini to be better while having less real estate.