It's gripping, confusing, startling, dumb, action packed and thought provoking. It is not perfect and half way through my brain started to hurt, but it is really rewarding and deserves multiple views I suspect to fully grasp what on earth is going on.
I can understand those who didn't like it, and even why, but the fact I need to see it again just to make sense of it, and the fact I never took my eyes off the screen would say this is a future (or past!) classic in the making.
I recommend it and hope others enjoy it as much as I did.