Well I assume you will be playing at DMZ as this is really the only field for active airsoft games.
I would just suggest getting something you are comfortable using. I would consider about 95% of the games played at DMZ to be CQB anyway as TacTown in the front has a lot of buildings and cover with not alot of cross field shooting.
Most of the games played in the woods are played in the shanty town area and also has a bunch of buildings and cover.
so just egt a gun that you like and you will do fine