If you purchased Infamous 2 or you are a PS Plus member, you'll have exclusive access to the Uncharted 3 Multiplayer Beta. If you don't have it now, it's too late, as the servers are being shut down July 14th for awhile until the full game is released November 1st this year.
There are 3 maps in the beta. The newest one being Yemen, which wasn't originally available at first, but updates are constantly being sent out. I find them a bit small in comparison to other multiplayer games, but not too small so that it's constant chaos (e.g Nuketown). And they're nicely done too. Lot's of tactical options for navigation.
I haven't played the Uncharted 2 multiplayer, but from what I've read, Uncharted 3 multiplayer is a step up. You have a new "kickbacks" feature, temporary enhancements to your gameplay, like spawning an RPG, speed boosts and cluster bombs.
The pace is very different from a regular FPS multiplayer, but it's a lot of fun. I like 3 team deathmatch, where you are paired up with a buddy and take on 2 other teams. And the controls are the same as the single player mode. You can scale up walls, climb ledges and monkey around.
Definitely something to check out, I can't wait for the full version :)