The single player is good. Multiplayer is definitely a big let down and not up to par.
However my biggest problem with GRAW 2 is the multiplayer. It sucks. Period. It feels nothing like the single player. There is an absence of the ability to use cover, aiming is awkward and slow, and there is a degrade in graphics. Multiplayer in GRAW2 as of 2009 is almost non existent and when you do find a game you often are sliding on the floor because of lag. For example, you will be at a wall and as you tap on the stick to peek right it takes about .5 sec for it to respond. Lag does seem to affect this game more so than the other ps3 shooters. Also, there is a variety of guns but they all sound and look the same. The scope rectiles they provide for you are all very generic.
Overall, as a multiplayer lover first and single player second, I can not recommend this game. Perhaps it is worth a rental but the multiplayer just leaves me unsatisfied and wondering why i rented this game.