Nolan has this bad habit of telling some concepts in a very didactic way. He uses Page's character, who is ignorant about the concept, to tell the audience how it works. It's a sacrifice he has to make, since the film needs a lot of time. If he stopped to explain in a more intelligent way, the film would last about 3 hours. It was a sacrifice, but it is still difficult to swallow those parts.
But other than that, the film works very well for all the other parts. My favorite part is the projection of Mal, interfering with dreams, disrupting the plan. It reminded me of Silent Hill 2, where projection ends up being a burden.
So yes, a great movie. Nolan used the things he knows how to do best, along with a very interesting concept, and a well-dosed drama that I liked.