Unless you're fully immersed in the hip hop community, and know all the rivalries, squabbles and in-fighting that's gone on since hip hop's inception, see "Beef" first.
I felt the producers glossed over too much of the pioneer days (EPMD, etc.), and the recreations were kind of silly and irrelevant. I don't think anyone well-acquainted with hip hop culture needs ominous music to relay the potentially dangerous situations brought about by the egos involved.
Aside from these minor complaints, I'd say this is an excellent documentary, giving the lowdown on all the "beefs" between acts from the beginning. I give it a 4 out of 5.