I've just got back from seeing it, and my mind is reeling. I think it was incredible. Going into the theatre, I feared that I might lose the thread of the plot, as it's said to be so complicated - and they're right, it is. But I thankfully managed to follow pretty much all of it, and love Christopher Nolan right now.
A funny little anecdote: when the lights went up, all the people around me immediately started apologising to each other for being a distraction, and no-one knew what the hell everyone else was talking about. Seriously, everyone in the theatre had been shouting out, gasping, making comments, but had been so enthralled that we didn't even notice that everyone around us was doing the exact same thing.
I've not got into a movie on that level in a very long time.