I prefer the AK in game because of the better cq spray, a more reliable headshot, and a predictable three shot burst with more power. I like it better for reals reals 'cause it's way more reliable, consistent, and packs more punch.
The AK all the way. Not only is the AK wickedly accurate in 2-3 round bursts, it kicks in such a fashion that the bullets go speeding toward the victims head. 70% headshot kills is proof enough for me, and my kd ratio is getting a little bit better as I get used to the pacing of normal CS:S.