First off, see this movie in 3D- the effects are very stunning. The battle scenes are very impressive.
The story is decent, but there seems to be an attempt to add in people that really don't need to be involved- such as Agent Simmons, Sgt. Epps -and the parents. It seems like they wanted to include EVERYONE from the former two movies (save for Megan Fox) and deviate the plot line to include...
One thing that really seemed out of character to me is that Optimus gets down-right brutal at the end of the movie; while the overall effect was gratifying this was not the Optimus from the start of the movie or the prior franchise.
Very predicable plot line 'twists', corny dialog and impossible saves make this movie not so good. The action, explosions and CGI make it very enjoyable to watch. A bit long, but they needed time to include all the extra characters from the other movies and give them a few lines.
I would definitely recommend seeing it in 3D- but I doubt I will be buying it when it comes out on Blu-Ray.