Windows: What's the Big Deal with Crysis?

I've played many games. Most have been good, some have been great, and a few have been terrible. Crysis isn't terrible. It is however, overrated. Here's my gripe. I just finished Call of Duty 4: Modern Warfare. BEAUTIFUL game! Ran well on my MacBook Pro under XP, had a great story line, etc etc. Now, take Crysis. I just installed it the other day and ran it for the first time. No, I can't run it at full graphics settings, but even at medium it looks like crap. My point is, how can COD4 look so good, run beautifully, and Crysis looks like shit? Some might argue it's the expansive free roaming element of Crysis but I don't know. The game's not all that.