This is the must own shooter on the 360. Yes, it's better than Gears of War.
The depth of the multiplayer is simply amazing. Tons of weapons and vehicles, all of which are very powerful, but they all have counters to them.
You really need to spend a few hours, learning how the weapons work, figuring out which weapons work better on which maps, working with your team to strategize how to counter certain other weapons and VSes. It's just really, really well done.
I definitely prefer the more phrenetic pace of Lost Planet's multiplayer to the plodding pace of Gears of War.