Well I've owned 11.5", 14.5" and 16" and have noticed little difference in combat style accuracy. I have also owned Armalite, Eagle Arms (also by Armalite), DPMS, SGW and a Bushmaster upper. They were all milspec and therefore little difference... milspec is milspec as far as I know. Now that said, here are some of my observations. I love my EA 11.5" the best because it is fast to move and very well balanced. A buddy of mine who scoped his gets better than 1MOA using quality ammo but for me I like combat style shooting and am cheap on ammo. The SGW I owned had a grey finish that looked kinda crappy and untill I put about 2000 rnds through her it would malfunction (double feed) every 20 rnds (back when we could use 30 rounders). But the problen fixed itself. I ended up putting a 16" Bushmaster upper on her and it worked perfectly, however the rich matte of the upper clashed with the sickly grey of the lower. The finish on the EA/Armalite and DPMS are great so I can't see much of a difference. Never owned a Colt. Hope that helps a bit but this is only opinion.
