I own 5 ARs. All 5 are NFA SBRs. Not one of them is a factory rifle and have all been built with the parts I want.
The lowers are.
Bushmaster
Colt
PSA
DPMS
S&W
To me the lower is just a lower. I care about barrel, bolt, and FCG, but beyond those three parts, the rest is just parts to me...