If you owned an 11.5" upper, which would be your 2nd choice & why.
All around intended purpose from home protection to fun gun. Would be used primarily with a suppressor.
10.5" just because you already have a 11.5", Get a Noveske kx3 for it!
BCM 12.5. The drop from 11.5 to 10.5 has several negative consequences that have been hashed and rehashed many times. Use of a can may negate them.