Recommended.
I should start off saying I'm not a Transformers fan. As a kid I'd occasionally see the cartoon and read a comic, but would say 'nope, not interested' and never really bother with it. But some friends wanted to see the movie and as a social thing I said sure. After all the special effects looked really good in the trailer.
I'm glad I went. The movie is high on emotion and high on cgi action. It also throws in plenty of humor part way through. Even though one could probably nitpick apart the movie from a critical standpoint, the overall movie just seems to click and work together. Kinda like a Transformer. It's something you know that logically it shouldn't work, but just somehow just DOES.
Among my bigger nitpicks would be one scene I thought was a little too hokey. The Transformers themselves looked great, except it was a bit hard to tell them apart at times. I think perhaps they went a little overboard with the robots, with all sorts of little intricate moving parts that ain't in the toys at all. I suspect that was put in to make the crowd go "cool" and to make that robots could turn into trucks more believable for those not familiar with the toys and would have a hard time suspending their disbelief. By the time they are in robot mode your left seeing a few vehicle like parts on them to identify them with. In between all that is a grey robotic mesh that's similar on all the Transformers. Also, the climax left me a bit puzzled, but whatever. I guess it works.
I wonder if the movie will hold up in a second viewing or over time, but as for the here and now it's a great fun movie. Remember Independence Day with Will Smith? Everything about that movie was bad from a critical standpoint, but I enjoyed it for the straight on emotional roller coaster ride that it was. This movie is similar, but not as bad critically. If you are a comic/sci-fan that was disappointed in X-3, Spider-Man 3, Silver Surfer 2, etc.. I think you'll find this to your liking.
I give it 4 stars. I'm tempted to read the old Transformers comic books now.