I just watched this and found it to be very interesting. I've seen several of Gates's other documentaries and this one is similar- it covers a very large topic in an engaging way, with the use of many academic experts as well as active members of Black churches (clergy and laypeople) as talking heads. And you get to see many beautiful churches and hear some great music throughout. John Legend is a co-producer, but he only appears briefly, as does Oprah.
I was particularly interested in the section about the early years of the church's history during slavery, and the various points of conflict between different churches in the community as time went on- along geographic, socioeconomic, and ideological lines. I also appreciated the focus on the contributions of women (in general and with lots of specific examples) in the growth and shaping of the church.
It definitely focuses on the Protestant churches (I think AME and Baptist get roughly equal time, with a little less focus on Pentecostal), but based on your comment I really want to see something about Black Catholicism now. I was raised Catholic, and would be fascinated to learn about the different traditions. There are two brief mentions of Islam in this, regarding enslaved African Muslims, and the much later Nation of Islam, but they're only passing references.
For anyone interested in this topic, I highly recommend it!