Finally -- a summer movie that almost lives up to the hype. I've enjoyed fighting robots ever since I watched Battlebots with my sons back when I was Eng on the Jimmy Carter, so I had high hopes for Transformers. Unlike with the other "big" summer movies so far, I wasn't disappointed (unlike this reviewer, who thought its theme of "victory through sacrifice" was too militaristic).
First, my complaints about the movie -- there were some continuity issues (the hot girlfriend's nail polish didn't match from minute to minute), and there were way too many 4-star Admirals (in SDBs, no less) standing watch in the NMCC. While the robot fighting scenes were pretty cool, they didn't do any Matrix-style slow motion that would have been appreciated by the techie portion of the audience. They also don't explain the apparent technology the robots use to make themselves (and especially their cube-shaped power generator) impossibly smaller when they're transformed compared to when they're in robot form. Mass is clearly not being conserved here.
On the good side, the military guys on the ground came across as the kick-ass defenders of freedom that we all know and love. (This helps explain why the regular Hollywood-type reviewers don't seem to like the movie very much.) There were a surprising number of really funny scenes -- in fact, those scenes were what made the movie. It's a film that movie-goers of all ages (up to probably 50) will like -- as long as they like explosions. Overall, I give it four conservation-of-mass-law-violating-robots out of five.