I thought the film was really quite excellent, but a tad short of the brilliant masterpiece it's being made out to be. Although, I've only seen it once, and we'll see how that changes my opinion.
Two things kept bugging me throughout the film, and they are of course fairly ridiculous nitpicks. First, the term "subconscious" is generally frowned upon in any sort of academic or scientific circles. It's more of a layman's term. People of this intellectual calibre should most likely be using the term "unconscious." And the dream time dilation is not a real thing, dreams actually occur in real time, and the entire premise of the movie relies on that conceit. So those were always in the back of my mind.
Of course, those two things are stupid when faced with the suspension of disbelief the film requires, anyway, so didn't detract from my enjoyment of the film too much.