Saw it last night on a "RealD" screen. Without spoiling it, here's the precis.
It was 3 hours. Do not drink soda in the early part of the film. I did not and I was happy.
It was gorgeous. It used but did not abuse the "RealD" 3D technology.
A huge selling point was how it got past the "dead eyes" "uncanny valley" effect of many high-CGI works previously. It ... really, really did a good job.
It was, yes, trope-tasmic, trope-tastic, and trope-a-licious.
But with three hours in which to show you the characters, even the obvious, in your face bad guys are allowed enough screen time that you can see there is more to them than that.
There were two places which got a HUGE audience reaction, one a disbelieving groan and muttering of disgust at the words coming out of one character (but ... they were appropriate to the character) ... the other was at the end. The audience broke into applause with some cheering.
I have not seen that happen for a movie in a very long time.
There will be people complaining later about the heavy-handed political message, the politics evident in the story, and even about some technical details. Ignore that. It's not important to what's really going on.
Watch the pretty. In a theatre if you can, or on the best quality HD TV you can find.