I saw it too, I was pretty disappointed. Well, not disappointed, as I didn't go in with any actual expectations, just unsatisfied I guess. To me, there are really only 2 absolutes in the Transformers universe:
1 - Starscream will actively attempt to usurp the Decepticon throne
2 - Prime is the baddest motherf*cker on the planet, and likely in the galaxy
In the new movie, Prime was a total pussy who got his ass handed to him by Megatron (who was inexpicably like 20 feet taller than all the other transformers??), and Starscream lacked personality. Of course, ALL the characters in the movie lacked personality. They were plot devices, not people. The plot, even just sticking to the story laid out by the film, makes NO f*cking sense whatsoever. At 2.5 hours, we don't get to see prime for the first hour, and Megatron is not even mentioned in the first 90 minutes. And this is a TRANSFORMERS movie??? Exactly WHO are they introducing these characters to? Is there somebody out there going to see this movie that DOESN'T remember Optimus Prime? I mean come on! On top of that, and this doesn't really qualify as a spoiler, the final battle scene takes place in a cramped, crowded city. That's right - characters who can, at will, transform into flying and driving vehicles duke it out in a civilian population center, and in like a 2 block radius at that. I don't care who you are or how many paint chips you ate as a kid, that is just retarded.
On the upside, both Prime and Starscream do get one decent action scene. But it adds up to maybe 4 minutes worth of screen time, out of two and a half hours worth. If you have any attachment to the transformers personalities or characters from the original show and series I really doubt you will like this new movie. If you want to see robots punching each other in the face, and some teen booby action, well, this movie DOES have that. But even then, it feels more like Gears of War meets The OC rather than Transformers...
I guess my issue with the movie is this. They could have gone two different routes with it and made a VERY good movie. The first would be chunky, classic robot designs, a tongue-in-cheek attitude, basically all-out fan-service. Jump right into the action, no dicking around with some marines in the desert etc. The second approach would be to put a lot of effort into approaching a realistic premise with some amount of logic and planning; engender a fear of complex technology in the viewer, get some real themes going on there, and make at least a minimal effort to provide a cohesive or sensible plot. Unfortunately, Michael Bay took the middle road, which resulted in kind of annoying bot designs, flat characters, and the biggest plot hole I've ever seen in any movie ever