I'm going to be an almost lone dissenter and say that when I (as adult) went and saw this in the theater I pretty much loved it, though admittedly it could have been edited down to a tighter story. I need to point out that I am NOT just an "all action" kind of guy either, and am just as likely to watch an intimate character driven film/show (with subtitles even!) as a big budget effects movie. Maybe for that reason I tend to watch a movie like Revenge of Fallen with an eye for cinematography as much as anything else. As an aside though, I will mention I hated the 3rd transformers movie of the series: "Transformers - Dark of Moon" but this review is for movie 2.
No, it's not perfect: Is there needless and distracting potty humor with the "twins" transformers? Yes. Was the language kicked up a notch from the first? Yes also. I need to point out that the one use of the F-bomb was so buried under the music and sound that I actually didn't even notice it until recently, (probably the 6th time I've watched it over the years) Did an inordinate amount of buildings, robots and people (more implied than actually seen) get blown up. Yes again. Did the overly skinny model decepticon talk sexy and push Sam down onto his bed? Yes, but sex itself was never an option for that scene as Sam was fighting back, and she was looking only to interrogate him about some information he had. So it's the sort of scene that would mean almost nothing to a kid because it was all by implication. Probably the older the viewer is, the more it would imply.
But too many reviewers focus entirely too much on the negative details and not seeing that there was a lot that's great in the movie too. And to say there were no positive role models and no character development in the film is ludicrous! For one, all of the signature Autobots are nothing if not "stalwart and loyal" throughout. They will fight to defend the humans with no regard to their own risks and don't ever take the easy way out. Sam (main character, college age) initially balks at being part of the interstellar battle of the robots, but eventually concedes that his own selfish desire to be a "normal" college kid will have to be put on hold, including being willing to die for the cause. His girlfriend, Mikaela, also sticks by him throughout, even when it seemed very likely neither would live through it. They are both in a committed monogamous relationship as well.
So again, a LOT of things get blown up, there is plenty of peril, violence and all the rest. But the question here is will it actually scare a kid, or "scar" them, or make them want to become a violent loner? I think not- in fact definitely not. I would ask you, how many storm troopers get shot in the Star Wars series? How many hands and arms get cut off?
I think as a parent my biggest complaint is the language, but actually I am starting to wonder how important that even is. Since our son who's 7 (when this is being written) never hear's that kind of language around the house, it doesn't mean anything to him when he hears it. If someone is upset or angry he gets that by inference, and if it contains words he doesn't know it just gets rolled into the mix. Recently he asked about the use of "a son of b****" in Avengers, which in content was not anger but surprise. Could have been "I'll be darned!" in a G rated movie. But we talked about it and that it was not a nice word, and not appropriate to ever repeat and moved on. In the end, maybe I see a lot of what many parents are afraid to show their kids too early as a good way to talk thorough it. Because otherwise it's going to come to him from somewhere else.
Even when violence is more explicit, again as long as it doesn't scare him and make him feel unsafe, we talk about it the sacrifices people sometimes have to make for the greater good. You can turn even what is essentially an expensive cartoon into something positive if you look into a little deeper. That's where I come from anyway and maybe this review might be more helpful than some of the others.