I got sucked into this again today. Played it for about 3 hours.
Really liking the online, the only thing that starts to get annoying the later you play is the lag. I was doing well on Recon earlier but the lag started towards the end and dear god it was frustrating.
Another thing thats a bit annoying is the fact that sometimes when snipers are hiding in bushes, they seem to be protected by the branches. You can shoot at them all day long and nothing happens. Happened to me earlier with a guy and it was like Naked Gun, the two of us looking at each other from about 5 feet away, him hiding in a bush and me running side to side trying to shoot him as he tried to shoot me. After about 3 clips I managed to move around enough to find an angle that finally managed to hit him. Hopefully just a demo gripe though.