Okay, I'm not going to lie. This review is going to be harsh and contain SPOILERS. If you loved this movie or don't want any of its plot points spoiled, do not ready any further. It's best for all of us if you don't.
Still here? Alright, let's proceed.
First off, let's get something clear. I enjoyed the first Transformers movie. I didn't mind the second, even though I understand why a lot of people didn't like it or found it offensive. Me personally it didn't offend, but then I'm not a member of any of any of the ethnic groups that would have been offended and I'm far from arrogant enough to think I should be offended on their behalf.
So why is Dark Of The Moon so much worse for me than the other two? It's boring.
Really, really boring. Even the "action" sequences got boring after awhile, and they were filled with giant, killy robots. My friend Jeff sitting beside me was yawning for the last little bit of the movie, that's how boring it was.
On top of that, most of the jokes in the movie were lame and/or came across as homophobic. The whole "Deep Wang" section was just so unnecessary. It was like trying to shoehorn in a little piece of The Hangover into an action flick.
And when the movie wasn't boring it was annoying. Shia LaBeouf's Whiney Whitwicky (patent pending) act was tolerable in the first movie, irritating in the second, and tiresome in this one. Part of me wanted to scream at him "Dude! No wonder that last chick left you, you whiney ass! Shut-up and enjoy living with your gorgeous English girlfriend who supports you!"
Speaking of said girlfriend, she really doesn't do anything in this movie other than make out with Shia and run around in tight jeans and heels. Oh, and show off her ass in panties in the opening shot of the film, just so that no one thinks Michael Bay has become gay when they see the "Deep Wang" section later. I have nothing against Rosie Huntington-Whiteley, but really, she doesn't do much of anything in this film. At least Megan Fox's character in the first two had some gumption, some spice.
Topless Robot has more here on what happens in this flick. If you need more reason not to go and see this travesty then check that link out.
Only take someone to see this movie if you really don't like them, or if they are easily amused by explosions.