...but, Transformers is awesome.
I suppose I should caveat that a little. Transformers is awesome, for a brainless summer blockbuster. The special effects and set pieces are nothing short of genuine brilliance, and while the script is hardly Oscar-winning material, it does have quite a bit of humour and the cast does pretty well with the clunkier bits. The characterisation is pretty weak, surprisingly even for the Transformers themselves, who (if anything) are a tad underused. However, and I cannot state this enough, as a cinematic spectacle, the action scenes are incredible.
The climatic end battle is absolutely stunning, especially when you've got Jazz, Ratchet and Ironhide taking on Devastator and Blackout. They've got serious Robot Fu. I was a little disappointed that they didn't do a little more with Megatron and Starscream; their whole relationship is glossed over in a single line and they're not in the film that much, which is a shame. My favourite Transformer in the film is probably Frenzy, as he's an evil little fucker, but also used for a bit of comic relief and he steals quite a few scenes.
They worked the relationship between Bumblebee and Sam pretty well, particularly the way Bumblebee gives hints to Sam about what he should do to woo Mikaela (the particularly foxy Megan Fox) via the car radio. Having the original voice actor for Optimus Prime is really a bonus, too, as it helps long-term fanboys like me have some sense of continuity and feel a little less like their childhood is being trampled upon. In all honesty, it's a heck of a lot less cheesy than the cartoon movie. And yes, I realise I must now be burnt at the stake as a heretic for saying that...
Overall then, it's definitely worth seeing. Leave your higher brain functions at the door and gawp at the big robots doing awesome things on the big screen. You won't regret it.