I think all the AA's are done pretty well, and balanced overall regarding various situations. I would say though that the amount they get to be used should be toned down a bit, though.
Sprinting - Two bursts in a charge, but not as long as they are currently.
Invis - 10 seconds per charge would make a lot more sense. The jamming of the user's radar doesn't affect smarter players at all.
Armor Lock - Once activated, do not allow another activation until another 10 seconds or full charge. Going in and out of it breaks the pace of the game, and just doesn't play right.
Jetpack - No real complaints, maybe only smaller burst usage. Using it opens you up to enemy fire, so that's a drawback, but it severely reduces map control. Lots of people spawn on Sword Base, jetpack to the room people are in, and chuck grenades in there. Difficult to defend that.
Thanks.
[Edited on 05.06.2010 11:03 AM PDT]