It's not a huge community like Battlefield 2. Nor is it empty either. Plenty of full servers to choose from for any of the game types, as mentioned earlier. The nanosuit adds a lot of variety to gameplay, although you'll definitely want to stick with armor mode in most cases. It's really the maps that I'm most impressed by, though. Especially some of the smaller, deathmatch styled ones that weren't included with the original Crysis.
I'm referring to Crysis Wars, by the way. It comes bundled with Warhead.