I thought it was great. I'd even go so far as to call it an accomplishment. It was Ocean's Eleven, meets Flatliners, with a little sprinkle of The Matrix. All this while creating a unique movie experience that felt fresh the entire time I watched it.
I think Nolan is going to have trouble because there is a lot involved with his "dream physics" and a lot of people are going to get hung up on it. This is the best guide I've found that explores the physics of it and provides various theories behind the show's mechanics:
The thing that has me hung up the most right now is when Cobb went to Michael Caine for a new architect. Where were they at? I can't decide if they were in a dream, or if that was reality. Maybe I'm wrong, but I have a hunch that Michael Caine's character is more than meets the eye.