Later than most, but I did end up watching it.
While the movie presents a real thought-provoking concept, raising serious doubts about what our minds can and cannot do, it seems far too logical, too convenient to be convincing at times. I agree with the NYT review that
Mr. Nolan’s idea of the mind is too literal, too logical, too rule-bound to allow the full measure of madness — the risk of real confusion, of delirium, of ineffable ambiguity — that this subject requires. The unconscious, as Freud (and Hitchcock, and a lot of other great filmmakers) knew, is a supremely unruly place, a maze of inadmissible desires, scrambled secrets, jokes and fears. If Mr. Nolan can’t quite reach this place, that may be because his access is blocked by the very medium he deploys with such skill.
The ending was mysterious. Did Cobb really wake up? or not? He is not shown to have actually woken up in the van that drowns, yet he wakes up in the airplane. So was that a loop where Cobb kept going down levels in his dreams to eventually surface in the present along with the others?