The gameplay itself is fine if you can get it to run right. The single player is fun, and coop is a fucking blast.
But I somewhat agree on the engine thing.
The developers decided that the only way to make the game look like Mexico was to use this Deferred Lighting HDR to give it that obnoxious glow. It can't be turned off without breaking other parts of the game (nightvision, to name one) and it is slow as fuck. Not only that, you can't use AA in GRAW. At all. Ugh.
I just don't understand what these people are thinking sometimes. HL2 hits and has HDR and AA and all the cool ass effects that it has, and it runs 20 times better than most of the games that come out that don't look half as good.