One thing to note - boosting in games like BC2, involves tactics like joining a HC server, choosing Medic, and constantly damaging/killing teammates, and healing/reviving them for xp. In Brink, FF damage results in losing xp, so tactics like this may not prove very effective. It also helps with griefers.
When you kill/damage a team mate in BC2 you also lose exp. You lose more exp then that you will get for healing/reviving them.
Atleast on the xbox it is that way..