Okay - my 2 cents... I have completed the game once in "game time" of 14 hours. Obviously with restarts and such, you could probably add another 5-6 hours. Therefore Playing the first time is problem a 20 hrs (if you are not cheating)
Graphically the game is what I expected. Generally well rendered but not the best I've seen. Cinematics are however more top notch and VERY good. Sound however is awesome.
Play is really an adventure/platform style more than an RE survival horror. Also I never ran out of ammo. The puzzles are simpler than RE but that's a plus in an action game. Although you play each chapter as a different character, they basically play the same. The general difference is weapon selection and character speed.
Replayabilty - I'm almost finished with the second time through. And although the story and monsters vary a little, the puzzles are the same. Therefore, I'm on Chapter 10 after 4 hours instead of eight. I will however unlock the eternal mode if I play through with each of the three scenarios. So I'll get a few more hours out of it.
My favorite part of the game is the insanity process. As you sanity is tested the game, very sucessfully starts messing with you, from furniture appearing upside down, to wondering if that's a real fly on the screen. I won't list them all here but it definitely makes this game addicting.