I've heard only good things about DPMS. When I went to build up an Oly Arms lower a few years ago, I used the DPMS small parts kit (trigger, etc.) and it was much better than the Oly kit I had used in a previous rifle I built.
olympic sucks in the quality control dept. dpms has problems to like very fussy with wolf (won't cycle corectly)and the mag well is to tight . if you are going to spend the money build from the ground up like a diamond lower from brownells and a good upper like something national match .
I picked up a used (mint condition) Panther Bull Classic, for a song and a dance (I suck at both). The only mod I made was changing to a .040 and .030 rear app. This rifle consistantly knocks down bowling pins (real ones) at 200 yards. I am also a newbie with the AR-15.