The game's totally awesome! If you're an online-gaming addict, this one is a MUST BUY!
First, it's not an FPS, and that's what I like the most about it. It's like a human version of Ratchet and Clank online. You can build an arsenal that can go up to 8 weapons; flamethrower, sniper rifle, wrench, rocket launcher, etc. The reflexes of your character are great, and if you get used to the physics and gravity of the world of Warhawk, no one'll stop you!
I must also talk about the vehicles. Flight mode is similar to the one in R&C too (don't you think the similarities between the two games are too much of a coincidence?), and you can get many weapons on the hoverplane, too, like homing missiles and cluster bombs. The tank and 4x4 car are also great to play with, especially when you're going against enemies on-foot :P
The cons of this game are these: the help log aren't so... helpful, you gotta discover things yourself - The shifting between driver and shooter in a 4x4 vehicle (for example) takes too long, you'd be dead by the time you shift - anyone can kill you while you're in a hoverplane; anyone with a rocket launcher, a tank, a heavy machine gun, a ground-to-air defense system, or even another hoverplane can get send you to the moon in a second or two, so you need to practice flying a LOT to get used to it.
Finally, lemme tell you something... I'll make ya an offer ya can't refuse :P no really, if you played BF2 or Counter Strike or Call of Duty 4 online or whatever, you'll definitely love this one.