They are fun to shoot and they shoot well. I have shot a friend's a few times.
Personally...I just don't like the looks of them. Too futuristic for my taste. I'm more of a M1A - AR guy, old school I guess.
Or just old.
I was going to buy one, had the money in hand. I stood at the gun counter for an hour looking at it and just couldn't "pull the trigger" on the buy. I bought another AR.
Maybe someday I get one since my wife loved shooting it and she complains about her M1A being too heavy.