Musical groups come together and they come apart, and even the ones that come apart occasionally get back together for gigs and another fan-tantalizing prospect of a new album.

So it is with A Tribe Called Quest, the subject of debut feature filmmaker Michael Rapaport's bracing documentary — a reminder, part "Behind the Music" and part something better, that even artists professing love and togetherness have a hard time keeping it going.

Members of ATCQ have expressed varying degrees of approval and disapproval regarding the film, which contains a fair amount of unvarnished acrimony during the seductive, jazz-inflected hip-hop innovators' 2008 Rock the Bells reunion tour. The subjects' mixed responses point, I think, to Rapaport's getting it about right. It's conventionally made but no hagiography, and often thrillingly alive.

Q-Tip, the chilled-out dandy at the center, has known fellow Quest collaborator Phife Dawg since they were 2, growing up in the same Queens, New York, neighborhood as Run-DMC.

"I had to sneak and watch 'Soul Train,'" Dawg says in one interview, regarding his churchy upbringing. His later health crises and mounting medical bills prompted the 2008 reunion on which Rapaport trains his camera.

The filmmaker comes at his subjects as a huge fan with all-access access, which is a plus, though in many cases a warts-and-all documentary can lead on-camera subjects to perform their anxieties and conflicts in a way that feels false. Here, surprisingly little of that.

The group formed in 1985 and recorded five albums from 1990 to 1998. Like Thelonious Monk's bebop piano experiments, Q-Tip's shaping of the group's soundscapes revealed wit and high-flying sorcery. No screeds or Public Enemy-brand provocations. His musical taste, as Q-Tip says on camera, came straight out of "my parents' record collections."

By the time of their fifth album, "The Love Movement," the love was seriously tested, and in "Beats, Rhymes & Life," the 2008 concert tour off-stage footage reveals four men (Q-Tip, Dawg, Ali Shaheed Muhammad and Jarobi White) struggling to relearn their own camaraderie. Rapaport intersperses interviews with rap and hip-hop players who came later and these augment our understanding up to a point.

The best material, however, keeps returning to the unstable power dynamic between Q-Tip and Dawg.

The latter has supported the film from the beginning. Q-Tip, not so much. After being mistakenly cc'd on a harsh email from one of the producers, regarding A Tribe Called Quest's potential profit participation in the movie, Q-Tip took to Twitter with a vengeance. He's still conflicted about how the film treats him and shows the dissolution of the 2008 tour.

"It was an opportunity to show the craftsmanship," he tweeted one follower July 1. "But instead reality tv sentiment was the way." One week later, he changed his tune for the film's East and West Coast premieres and tweeted: "NYC/ LA stand up! There is a movie out there that is a slice of hiphop culture called BEATS RHYMES and LIFE! SEE IT!"

Well, we all change our minds. Anyway, he's right. You should see it.

"Beats, Rhymes & Life: The Travels of A Tribe Called Quest"

Grade: 3 1/2 out of 4 stars

Genres: Documentary

Running Time:98 min

MPAA Rating: R