Predator isn't 100% balanced, there's some cheap stuff with Ustanak and Agents. Compared to Survivors it's might as well be Chess though. Onslaught is the most skilled, most balanced mode IMO, but 1v1 is pretty boring.
Predator loses its novelty fast. Every game is similar. Rounds are too short and Ustanak needs more health. Everyone using shooting wild means a dead boss in 20 seconds.
Survivors does get better the more you play, but it still sucks. This mode brings out the douche in most players also, but its the most popular here on 360.
Onslaught is the best, but its dead. And 90% of my opponents pick RE2 Sherry which is boring.
Rounds are perfect in my opinion. Just imagine them being longer with a game of 6 people. 2 minutes for each person is good, so that's 12 minutes total. And 2 minutes against the Ustanak is forever when you're the last one standing and trying to stay alive long enough for the rocket launcher to spawn or for your team mates to revive themselves.
Predator got some glitch. Sometimes, I try to grab the agent, he just won't grab the agent.
Onslaught is great. But beware, if your opponent didn't kill any in 30 sec, just kill one and send him/her one enemies to force your opponent to start killing.
Survivors really make me lol...
It's not a glitch at all. He has a certain arc where people just get grabbed. There are a few exploits to avoid being grabbed (which is shared with you in the loading screens as well), but if you're good you can predict his moves quite easily and avoid him by dodging.