I have both the M&P 15-22 and a
Tippmann. Thousands of rounds through both.
My 15-22 has a polymer/fiber receiver is it is quite a bit lighter than a regular AR. That may be good or bad depending on who is shooting it and why. The magazines on the 15-22 load a bit easier than the Tippmann. That said, the Tippmann is the one I gravitate to because it has both a metal receiver and heavier barrel so it feels more like a real AR. The Tippmann mags can also be a PITA to get to feed sometimes - you have to pay attention when loading to ensure the cartridges don't get wonky in the stack. Once I figured that out, the Tippmann has run 100%. All I do to either is occasionally wipe them down and re-lube. A lot of fun for the money here.