Great in theory, mechanically it's shakey.
So you get faction benefits (as you would expect) for belonging to a faction. This comes in the form of discounts, favors, or items. Likewise, you can earn the anger of a faction, and suffer punishments from said factions in the form of markups, targeted harassments, and so on.
This is fine. I particularly enjoyed the results of being targeted by a faction.
My only real problem is that while the Zhentarim are in here, that's the only default faction. And while I can understand wanting to draw from lore and expand the factions, it was all filled with factions from the author's game. It would be arbitrary to map these to existing factions (either from 5e or earlier) but it is a bit of a disappointment.