I have several tier 2 & 3 AR 15s, LMT is my #1 . I want to buy a KAC SR15, a Colt 6920 and a BCM 16" mid-length. I am looking to replace the #1 slot with one of these 3. I really like the KAC (I like all 3 really, but only can afford 1 now). What does the KAC SR15 offer that the others dont? The cost of the SR15 is about the same as the BCM 16" & 6920 combined. Any advice