I thought it was a damn good action movie.
You all knew Micheal Bay was directing and this movie was basically Micheal Bay's standard, entertaining-as-hell action movie but with transforming robots. Awesome showcase of military hardware (Bay loves his helicopters), some laughs, and beautiful shots. You can't really expect much more from the guy.
Of course, I didn't grow up watching Transformers (did watch Beast Wars though ) so I can't comment on how much he ruined the characters. Optimus Prime saying "Sorry. My bad." was the funniest thing I've heard in a while though.
Also, watching this and realizing how much Micheal Bay's movies are all alike, I have no idea how that guy is gonna direct the new Prince of Persia movies. I don't remember seeing any helicopters in the game.