2012 is positively brilliant compared to Transformers 2.
First, though both are 2.5 hours, 2012 doesn't need an hour trimmed out of it. It isn't padded with totally unnecessary pot jokes and wrecking balls subbing as testicles. Bay is a boy who can't be told no so he does way too much. He's lost all restraint.
Second, 2012 though positively preposterous, takes at least a moment or two to focus on people - those parts you want to skip. It tries to give you a reason to care about the characters - albeit shallow - but at least there's an attempt.
Third, that attempt is to try to make sense and tell a story. Bay certainly doesn't care about telling a story -just blowing things up.
You can't get too deep with either of these guys, they both tell totally ridiculous stories, and neither make a lick of sense. Yet when I walked out of Transformers 2, you knew you saw crap held together by amazing effects. The crowd all talked about how bad the story, the acting, and the people were. But when you left 2012, it didn't feel like a wasted experience. It not only had great effects but it had interesting characters trying to be noble, trying to elicit real emotion. You didn't feel like you just watched the loudest video game of your life.
It's all a matter of perspective, and if given the choice to go back to the theater and watch one again, it would be 2012.
(I doubt that makes any sense, but I'm at work and should be working.)
Avatars are cool.