What Megan Fox destroys with poor to nonexistent acting, she makes up for in looks. Shia LaBeouf is a better actor for sure, but he doesn't have as much backup as Fox does. He's annoying.
I enjoyed the second film more then the first, mainly because the bot battles are brought up a notch. In the end, it's about the transformers and not the people that go along with their schemes. I wouldn't care if they replaced all the actors (the ones playing people).