I'll apologize in advance if I offend any of the fans. I watched this in IMAX 3D, and the 3D effects and action sequences were spectacular. But sadly, it ends there:
IMO, it's better than the 2nd movie, but it is still a movie built for a generation with short attention spans. Poor storytelling, bland acting (a complete lack of chemistry from the lead actors was a particular "acting highlight"), insane pacing, and a plot so full of holes that the Autobots could drive through it. Most of the time, I could not make sense of where everyone was going, what was happening, and even distinguishing the bad robots from the good ones.
I give it a 2/5.