Not that anyone asked, but here's my impressons so far.
Everything seems much heavier and clunkier compared to Uncharted 2. Greande throws, jumping etc. It's not a big negative, just takes some getting used to if you've come straight from Uncharted 2.
Any skills you might have honed in Uncharted 2's multiplayer won't necessarily put you at a massive advantage in Uncharted 3 as it feels like a very different game. (At least at the lower levels).
5vs5 Deathmatch with PowerPlays and Kickbacks is a bit of a clusterfuck. If you're in a good team and doing well expect to have a power play popping up every 40ish seconds for the entirety of the match. - This mode is no good for competitive play.
Hardcore Deathmatch is pretty cool. It strips back all the crap and should be much more familiar to Uncharted 2 veterans. - This'll likely be the mode Clan wars take place in due to it's simplicity.
Co-Op Arena. Again very familiar to Uncharted 2 veterans, although the gametypes change on the fly instead of being stuck in the same gametype for 10 rounds. Includes Siege, Survival, and GoldRush.
Three Team Deathmatch - I LOVE IT! Get one good team mate and you're set. Kickbacks are still in play, but PowerPlays aren't which is a much better balance IMO, plus you won't have to sit through the pre and post game cinematics.
The menus aren't as intuitive as Uncharted 2's, and seem a little convoluted.
Uncharted TV is a very nice feature.
If you're a low level you'll get crushed by higher levels because they'll have unlocked weapon upgrades and better boosters, and they'll also have more money to spend on the 3rd booster slot, Paid boosters, puting them at an even higher advantage. However, by around level 11 things start to even out a bit.
I'm an Uncharted 2 veteran, and I don't see myself spending much time in the PowerPlays 5vs5 Deathmatch because it seems frustrating (particuarly at higher level play). But I'm loving Three Team Deathmatch so far.
I'd like some deeper character customization for your created skins. I want to create Indiana Jones.
I forgot to add, it's the same noise for an assist as it is for a kill. It can be confusing.