Some people here have X ray vision and can tell the difference between 161 and 162 ppi. For these exceptionally gifted human beings, the display is not better.
I suspect that for the rest of use mere mortals, the Mini screen will look gorgeous and better than the iPad 2.
So "someone" can answer your question, but the answer will depend on their visual acuity and superhuman perception capabilities.
The only reason I'm asking is because I sold my 3 for 500 and bought a Mini.
I needed a smaller device and this was perfect. I just hope the screen doesn't burn me.