Depends on how much it interests you, I guess. I've listened to countless interviews with members of the church (mostly his daughters) on tv and radio, and I just happened to stop on the program description long enough to see what it was about. So, I had to DVR it. I have been so perplexed by these people since I first heard their name mentioned. It's got the train wreck aura, to me.
I'm even more confused after watching the documentary. It appears that the only members of the church are his family. They didn't say that, but they didn't interview a single member of the church that wasn't offspring of Fred Phelps. Another thing I found interesting, was that they taped some of his sermons, and the camera NEVER panned to the audience. Makes me wonder if there even is a following, that's not related to him.