I'm mucking around in the CS:GO closed beta and having some fun when I jump in there. Haven't been overly impressed with MW3 and its super spammy over the top constant helicopters, gunships, hardcore BS. The matchmaking and lobby waiting is as bollocks as it ever was. I can't comment on the competition side of things for MW3, not sure exactly what's the deal there. I think I would quite enjoy some old fashioned S&D
I would suggest Tribes: Ascend if you are looking for something competitive, fresh and fun. We have quite a good amount of TOGs enjoying it and it is free to play so no hassles to try out and see if you like it.
Obviously, Arma2 has been getting a spanking in Dayz zombie apocalypse. If that floats the boat!
Red Orchestra 2 is great but definitely on the more realistic, WW2, slower paced, challenging / punishing gameplay side. I like to think that each kill in RO2 is worth about 10 kills in any other game