Two things.
Matchmaking: Takes a little too long to join. And why can't I have another match with the same guys? Why am I kicked out and forced to find another random match?
Stealth Kill: This really pissed me off. I was playing as Predator in Predator hunt. I see a Marine pass under me, with his back to me. I drop down, I see the indicator for stealth kill, I hit it and nothing. The indicator came up twice and nothing. I immediately died.