Thanks J., I'd say one of my favorite features is being able to swap uppers so easily. Yes, should be easy for all AR's but believe me, sometimes it isn't. That DPMS .204 is an absolute screamer and makes little entry holes and big exit ones! Then dropping in the .22LR upper for some cheap fun is icing on the cake. I've tried a couple of other .22LR upper and the DPMS is the one that has worked the best and been the most consistant. So you know, this is my $ talking, no freebies for positive feedback. If it works I'm happy!
As I have also said, find what works for all your requirements then get it. Don't be surprised though if you find there's a waiting list for the good stuff.