I saw the movie too and would strongly recommend you to do the same, no matter what side of the aisle you are in.
If you expect Moore to bash only G.W.Bush, you'll be surprised. Although GWB is the most pounded, you'll see him attack the media, the military (lightly), congress (lightly), the Saudis, even the democrats.
I am not a democrat nor a republican, but one thing I can tell you: I never saw a movie that people would applaud at the end and would stay seated for a little while as if it was too short, even though it is almost 2 hours long.
Michael Moore is fat, ugly, ill-shaved... but he's a heck of a filmmaker. How can a guy with a camera and the help of a few other people produce a documentary that makes 8 million dolars in its opening day alone? He's competent!
Of course this is my opinion. See this movie and form your own.
Observador.