The game is amazing. Classes feel incredibly well balanced, graphics are a mind-fuck. I think Corinth Highway is the best looking moment in any video game I've ever played, hands down. Weapons are incredibly well balanced and do just the right amount of damage. My only complaints are (besides things being fixed that were announced in the patch) is that the WASP is a holy fucking terror on Corinth Highway and I think they ISA's search and destroy targets should be out of range from the WASP much like the Helghasts' are. Right now, the ISA S&D mission can get shut down from one or two Higs on the WASP turrets @ the museum. If you can't get up there to take them out, it's pretty much game over.
Other issue is with the Turbine Concourse map. The ISA is incredibly favored over the HG side. The ISA side has outdoor base turrets that will kill you even if you're not near the base. Not to mention there is much more cover on the ISA side and is much harder to access.
Other than that, this is probably my favorite multiplayer game ever. Well done, GG.
Edit: Also, the fact that there are STANDARDIZED servers is the best thing to happen to Killzone. I hated searching through KZ2 servers to find a Warzone game that had all the modes and all the classes and shit. It's very nice to just hit "Join Game" and be automatically put into the default game mode.