I've had ARs with various barrel lengths,
7",
10.5",
14.5",
16",
20".
So far,
my LMT 10.5", with a rigid non-telescoping ACE ARFX butt, is my favorite for fast handling and short range games.
But,
I also have a 16" 6.8 SPC upper,
and an AR 10 in .308 Win,
for the longer games.
PS: the 10.5" is LOUD!!!