The first movie was bad. The awkward masterbation joke in the middle of the movie was too much. The humans were the main attraction, not the giant transforming robot cars.
The second movie was worse. It had fewer scenes with the giant transforming robot cars, choppy dialog, loose story with glaring plot holes, more scenes with the unnecessary humans, and stereotypes.
The second movie did have a drag-out beat-down fight with Optimus Prime vs Starscream, Blackout, and Megatron where Optimus said one of the coolest lines (I'll take you all on!) that should have been accompanied with the music "To the Threshold." It also did have a brief battle with jet-Prime versus the bullcrap-baddie where he pulled the robot's face off. It did have a couple of good points, but so few it hurt rather than helped.
The third movie sounds stupid. The space race? really? But I will give it the shadow of a doubt because I am a Transformers fan. This is the last of these movies, and I'm waiting for another director to look the movies over, crap on them, and make it right next time. I just hope it won't take another twenty years for that to happen.