It is faster and performs better than the iPad 4, but not quite as fast as the iPad Air. The iPad Air has the same A7 chip, but the mini has a slightly slower clock rate. I own both the iPad Air and the mini with retina, and I cannot really tell the difference in performance. The mini is easier to carry, costs $100 less and it does everything as smoothly as the Air.
Better display kind of like the differance between standard display and hd on tv's. The reason I went with the retina display is the the last updates is on the newest ipad mini. The regular ipad mini is iOS 6 and the ipad mini with the retina display is ios7. I love the camera on it, the tablet and everything about it. The only thing it doesn't have that I wish it did is a flash for the camera. But most tablets don't have that.