Well, I think that gameplay sucks, because covering system isn't working properly, animations aren't so good and you don't have any interaction with the environment. It's just poor when you compare shooting to Gears of War or sneaking to Splinter Cell.
I say this: be ready for the worst and you may actually be surprised. :'P
But it's nothing, for me it's the best game since Deus Ex and I completed it something about 15 times. Those dialogs, characters, consequences... it's all worth it.