Really? I play BF3 in weekends with some friends, and i had no problems until now. I switch weapons and accurate shots and response is great. Maybe you are just a bad player.
No offense, but if you are bad at games, it's your fault, not your hardware's.
I haven't used a Roccat yet, so i can't say anything about their mice, i just say i have a good wireless gaming mouse which gives me freedom from creepy wires (when it's charged, of course, +24 hours is good time for me, i don't play more than 5 hours a day), is very responsive, has good features, feels confortable to my hand and gives me extra button i found usefull in many games, like BF3, Diablo 3, Modern warfare and other games.