i have the dpms ar-10 and i love it, it takes all mags unlike the aramlite
DPMS uses the same pattern as some others, but it does not take "all mags", not Armalite, and not FAL (like Rock River). Oh, Armalite just introduced a model which uses the KAC/DPMS/Pmag pattern (but in their case they are just going back to their original pattern)
Oh, DPMS does not make an AR-10; it makes a 308 AR-style rifle, but only Armalite makes the "AR-10"...and they have the lawyers to prove it.
Anyway, I have a DPMS, although it is a 20". No problems that were not of my doing (knocking loose the gas block on a prop during a match).
If money is no object, then LaRue PredatAR or OBR depending on weight tolerance and features. On a budget, DPMS is fine, but be sure it has a trigger upgrade - I have no good things to say about the stock DPMS trigger.