I have 3 DPMS rifles. 1 I assembeled from parts (cast lower) and it has worked fine with a great parts fit. The other is a lefty A2 (for my brother) that has about 3k rounds through it. I would call it a picky rifle, but only because it seems to have problems with the same lot # of Q3131 that everyone else has, but shoots all of my handloads w/o any problems and just seems to love Wolf (I know, I know, but I started this rifle with Wolf just to see what/if it would break it and it hasn't yet).
The 3rd one that I have is my NM DCM rifle. The only thing I've ever done was to put a Jewell trigger in it and have Compass Lake Engineering look over it and put in a hooded peep sight on the A2 rear sights. I've shot it a total of 2987 rounds (from my record book!) and it has never failed me once. I hold a Master rating, and next year I will probably rebarrel with a Kreiger just to keep my confidence level up.
I have had better luck with drop free (max spec) magazine wells with DPMS than any other brand. Doesn't mean that they rattle, but all 100 of my 30 rounders and all 72 of my 20 rounders drop free from all 3 of my DPMS lowers. The only other one that I have that even comes close is my Colt SP1(about 90%), followed by a tie between my Bushmasters/RRA(about 75%), with last being my Mega/Aimeetec/Grizzlys (at about 50%). I absolutely hate the one and only Oly that I have ever owned, and sold that lower but kept the 9mm A1 upper(flawless).
I like my DPMS. They've always been good rifles for me, and several of my MUCH more expensive ARs have had tons of problems.
Depending on the lower, it will probably be black annodized and then teflon moly coated. Mine wear very well, as hard as my Colt/BM. Very black.
I work at a gunshop. I keep track of the sales log and the repair log for the gunsmith. We sell about 6-8 ARs a month, combination of BM/DPMS/Oly/RRA/Colt, in that order, as well as any custom order. I cannot locate a single Colt, RRA, or DPMS repair that required anything other than a cleaning first and some owner education. We have a repair rate of about 10% for BM, and A LOT higher (6x) for Oly(mostly the Plinker model). This covers rifles sold from 1998 to present.
As a guide, of the guns brought in for service, about 75%, especially semi loading pistols/rifles, only require a detaiiled cleaning and proper lubrication to restore full function. About 10% are ammunition related, and the rest are actual material failures related to abuse/design/wear/fabrication material that require parts fabrication/replacement/fitting.
I hope this helps.
Tom
edited to update my numbers.