Interesting that this doesn't have any reviews. So far, I think it's the best documentary out there about the world of e-sports. I'm not an SSB player, but I found each character compelling for different reasons; in four hours, you'll get to know seven people very deeply, each of whom has their own playstyle and personal flaws. Maybe 1/4 of the screen time is spent on SSB gameplay, which becomes more and more interesting over the course of the series as you learn more about what's going on.
If you play or watch any kind of e-sports (I'm a Starcraft guy, myself), definitely give this a shot. But the film can appeal to others, as well; I have a roommate who is a total non-gamer and football fan, and this blew him away. Be warned, though, that the documentary gets a bit repetitive after the halfway point.