If you buy an Armalite AR10 lower, you're committed to buying an AR10 dedicated upper unless you don't mind the gap at the radius between the upper & lower.
Some feel the KAC/DPMS magazines feed better as early Armalite M14 mag conversions had problems. Armalite committed to M14 magazines because of the magazine ban preventing the new manufacturing of magazines with capacities greater than 10.
Armalite has worked extensively to make changes in their Gen II magazines to ensure reliability.
The advantage of the Armalite receivers, both upper & lower is that they are forged from 7175 aluminum alloy which is stronger than the 7071 alloy used by others. Not that there is anything wrong with 7071. The 7175 is a bit of insurance for a 308 caliber AR.
Your choices boil down to better alloy vs magazine availability.
I cannot afford a KAC and I'd rather have an Armalite than a DPMS. As for other choices, I'd much rather have forged AR receivers than billet receivers
Last edited by MistWolf; 10-01-10 at 13:29