Got it today and been playing the entire evening and it just went by in no time. It might be linear and the jungle stuff might not be up to Crysis' par, but damn its in just having so much fun with this. Shooting is pretty awesome (Even though I didn't like it that much in the demo, it gets a lot better the more you play it), and the platform'ish stuff feels very linear, yet they put in enough twists and big cinematic moments to make it feel like a movie. Good stuff. Plus I actually kinda like the characters, Drake isn't as generic and annoying as I had feared.
Best exclusive PS3 game so far, no question (Although that doesn't say a lot ;D)
Just hope it isn't too short D: