Some of her best material isn't even remotely funny, like her song that is a tribute to "Abraham, Martin, and John," the three victims of assassins, two of whom she had known personally. It is pretty amazing what she managed to sneak onto TV in her few performances in the 60s and 70s. Thank goodness for The Smothers Brothers and a few other shows that invited her on, regardless of her peculiar look and performance style, so we have at least a few images of her at work.
Whoopi does a pretty good job of keeping her own personality from overrunning the documentary (except maybe in the title), and has a nice lineup of academics to help frame Moms' work historically and philosophically. In addition, virtually every important black comedian who was alive when Moms was working is interviewed, and they give very smart analysis of why her work was so monumental at that time. Moms was one of the few women working in comedy at the time, one of the few black comedians to make it into prime time (and had 20 comedy albums in her career), and was also a lesbian, making it even harder for her to the type of attention that typical women performers needs to be successful. (I think they could have further explored how that helped create her onstage persona.)
This is definitely worth viewing.