Let's face it. Every documentary is biased. No matter how objective (forgive the situational wordplay) a documentary filmmaker wants to be in presenting his/her subject, he/she has a point of view, or else why bother making the film at all?
The problem here is not Michael Paxton's bias, although he is clearly an adoring fan of the writer/philosopher. The problem is that in painting a portrait of this equally celebrated and vilified woman, he never shows, and only barely tells of, the vilification. As a result, he doesn't give viewers, not even her most ardent admirers, reason to celebrate her.
The film mentions in passing some of her flaws as a person, and repeatedly talks of the criticism surrounding her ideas. But we never hear any of the criticism, any of the arguments against, anything at all to cast her in the light of "defender of the faith," or defender of anything at all, for that matter. She states her case time and again, in interviews, in excerpts from her novels and philosophical works, etc. But we're left with a feeling of "Great. Why should I care?"
Not many people will see this film -- 2 1/2 hour docs rarely draw the masses in theater, on video or anywhere else -- so I'll make a rather simplistic analogy. Think of "Star Wars". How compelled would we be to root for the good of the force if we hadn't heard Darth Vader expound on the power of evil (the Dark Side)? How can you convince anyone of any point, positive or negative, without at least presenting the counterpoint?
Viewers who already adore Rand will no doubt cheer this film. For them, it's very palatable candy. Her detractors shouldn't waste their time. But a documentary is supposed to educate viewers in some way, and the uneducated will get nothing more than a biography and an unquestioned statement of philosophy. That's not much for any doc, but especially for one this long.