Both. You can't change out the handguards to a free float system and it's a polymer gun. The upper is not mil-spec and I wouldn't dare shoot 5.56 through it.
It is really getting boring that reviews are posted by people that haven't a clue about what they are talking about. Well I guess that isn't anything new, most people said the same thing about Glocks when they first came out.
Get the gun that suites you best and gives you the best deal. As to C-15's I think it is a very good gun for the price.
This one's had over 1,000 rounds of 223/5.56 through it.