Michael Moore does cross the line twice with the "harassing people who aren't prepared to deal with him" thing, but for the most part, this film is even-handed and very well thought through. And the fact is, sometimes catching a company with it's pants down is the only way to make them do the right thing. His technique, whether honorable or even appropriate, is absolutely needed.
I've seen positive change enacted as a direct result of his work. I can't say that about a lot of people.
So, yes. I don't always agree with what the man has to say and I'll nitpick his methods until I'm blue in the face, but at the end of the day, I'll always admire him.