Not bad but not great
The biggest problem is, it is so linear that any form of exploration is negated by invisible walls. You know pretty well throughout the entire game which way Naughty Dog wants you to go. Conveniently placed explosive barrels are placed at every critical point on your journey and you become well aware that if you don't shoot these barrels you ain't goin' nowhere fast.
Once the lustre of the visuals fades so does the gameplay ... It plays almost like a FPS disguised in a third person view ... run, shoot, run some more, shoot some more and on and on it goes.
Rent it and finish it in 7-10 hours and you will have had some fun. Personally I don't think it as an outstanding game as some of the PS3 fanboys seem to rant about. I think 8.0 is just about as much as anyone should give it realistically.