Been playing W@W since I got it last year and really enjoy it. However, earlier I put COD4 on for old times sake like and I have to say, what a difference. COD4's graphics seem to me at least to be much better/clearer and the gameplay just seemed better. I do still really enjoy W@W though, especially the guns. I love snapping shots off with an unscoped Arisaka, really satisfying when you get a good one.
I don't think W@W matches COD4 though. It is, in my opinion, just better. Inifinity Ward really hit the nail on the head when they developed it - the uniforms for example are the same as the ones we see daily on the news and so are familar to us, and the majority of the maps also have that dusty, sandy familiarity we associate with Iraq and Afghanistan - something we gamers can relate to and empathise with. Going back to WW2, was a massive mistake on Treyarch's part, even though I find the online game very playable. I won't write Treyarch off as a developer though (even though their Head Shed/decsion makers need a good slap and need to be told to listen to what the buyers want), W@W campaign has some promising elements to it which they can build on and intergrate into the online game (HINT to Treyarch/IW - people buy the game mainly to play online!!! The campaign mode is a nice diversion, that's it!).