I thought it was...okay. The special effects and the action were top notch, and the story was kind of interesting, but it was all buried beneath way too much expository dialogue and
way too many comic relief characters, most of which were complete failures.
Skids and Mudflap added nothing; the movie would have been better served if they'd been excised completely and Bumblebee made Sam's sole Autobot companion, like in the first movie. Sam's college roommate was completely pointless, and shouldn't have been in the movie once Sam and Mikaela left the college. Sam's mom was
way over-the-top, and not in a good way. Simmons was funny, but did we really need to see him in a thong? And was Devastator's swinging ballsack supposed to be funny?
Optimus being absent for a long stretch of the movie really hurt it, I think. I get what they were trying to go for in paralleling what happened to Megatron, but Optimus, IMO, is the heart and soul of Transformers.
He is the star of the show, in every incarnation. I want to see more of him, not more of Shia LaBeouf running around dodging 'splosions (though I don't really have a problem with LaBeouf, like a lot of folks seem to).
I'm really glad they decided to ignore that Bumblebee got his voice back at the end of TF1, though. He's a lot more fun when he can only communicate through audio clips.