I thought I'd try this game on max settings just to see what it could look like and its amazing quality, definetly impressive.
Unfortunately I forgot I had 2xAA on so it was like 10fps on my x1950pro
Everything in the background is real but you cant ever use it because its out of bounds, its nicely done because as you get closer it just gets more and more detailed. The sea bed looks great too except then you die of no oxygen, etc
Even if the gameplay were junk (remains to be seen), you could just leave it on spectate mode as a screensaver
Crysis have been working with mod makers from the start luckly so its not all down to them wether its good online or not.
Here are some links :
http://www.obsidianedge.net/forum/viewtopic.php?p=9261#9261
A quick comparison of model detail seemed to show a maximum of 20000 polys for a crysis vehicle vs 8000 in BF2
http://www.gamershell.com/pc/crysis_obsidian_edge_2_mod/screenshots.html