I've been using a mini since 11/2. Seems the same to me now as the first day. Is it as crisp as the retina display, no. Is it fine to use, for me yes. I just don't understand those that used non-retina displays for years, then the retina iPad comes out and now everything not retina is unacceptable? Just nonsense.
It comes down to if you want a lighter, smaller iPad. If yes, get the mini. If no, get something else. It's really a very simple decision.
People just don't want to go back after becoming accustom to the better screens. Having a retina MacBook Pro, iPhone, and iPad you get use to the technology. It isn't that it is bad but rather we have just gotten use to the higher resolution. If we never had retina I do agree the mini would be perfect but we do have retina. The day apple releases a mini with retina display I will be purchasing one.