The physics was done right, in all aspects. I was very pleased with this. Special effects were well done. Nothing looked hokey.
Much of the movie seems rushed. Some of it is pacing, and some of it is story elements. It needed another hour to really fit things in properly. Some terminology was omitted until the very end. I didn't get it as a nod to the books. It really served to reinforce how much was trimmed from the movie. I think making it an epic movie would have done more to bring people in for the next movie, or for re-watching of this one.
There were tech changes, and one story change that I didn't really like. They did this to fit in one concept from another book. Some of the trimmed elements really were needed to support this. I think they could have left out that element and picked it up in the next movie. On the flip side, without the element in this movie, it might not have drawn people into the next movie.
The changes overall seemed to be set up to forcibly require a sequel to be substantially rewritten vs the books. Or maybe it was made on the premise that there wouldn't be a sequel. Either of these options disappoint me.
Paying IMAX rates weren't really my favorite. It would have been just as good on a normal screen, though 3D would have been nice for once. IMAX is really more about fitting more people into a theatre at once it seems. Though, the details were pretty good.
Even with all of my complaints, I still call this an 8 on a 10-point scale. Definitely worth the watch. I wouldn't cry if I had to see it again.