I dunno, I was more impressed by Crysis. COD4 is merely OK for me. I think I actually prefer COD2. Maybe it's lack of cognitive dissonance, but there are so many things that seem so...silly...in COD4 and you get the feeeling that that wasn't the intention. It feels like the Sum of All Fears movie...where everyone seems to be acting serious, but taking a step back you start thinking how silly it all is. COD1+2 felt like WWII action movies. But there's something...slightly annoying...in COD4 to me. Nitpicks. Overall I like it.
Crysis on the other hand, it's like a really great summer bloackbuster. Predator. I guess that sums it up for me...COD4 was Ben Affleck trying to be serious in Sum/Fears...Crysis was Arnold fighting cloaked alien in PRedator. I liked PRedator a lot more... Just my 2 cents.