All right, I've seen the movie, but there aren't any spoilers below.
The plot development, or lack thereof, is the main beef I've seen in reviews. They're right, to an extent. The plot is strong, and it is there. It is fully developed, but it doesn't have an intermediate. It goes from one spot to another with lightning speed without taking the time to develop it. Another few minutes placed strategically would have made all the difference.
The action? Absolutely magnificent. I'm still amazed at what technology produces these days. There were only two places I can legitimately say were just way too bad and should have either been done differently or taken out, but you can easily look past those. The other two movies had as many, if not more, such moments.
The main beef I had with this movie was the cheese. There were far, FAR too many cheesy bits. In fact, one bit was so cheesy I thought the movie was going to proceed a moment and then jerk us back into reality, with a kind of 'fooled you' reaction. Instead, it quickly ended the scene and was used as a transition point. A bad, BAD transition point. Why don't some of you, when you watch the movie, come back and tell me what moment I'm talking about. You'll know the moment, bad music and all.
The movie overall? I'll give it some major cool points for the action, a few cool points for a good plot, but withold a few cool points for lack of plot development, and flat out take a few away for sucky cheesy moments. I really enjoyed it and was able to look past the deficiencies and really enjoy the film.
But watcher, beware. Watch the film for what it is: A very cool action flick with a few nice mental points. That's it. None of the deepness of the first two (of which the first was the best), but some good stuff nonetheless. I'll give it a thumb up and a thumb sideways.