Spoilers ahead: The first few episodes are excellent, but it drops off in quality near the end. Its unique mixture of different mediums, though overplayed in some areas, provided interesting shake ups in the action. The Aquaman knockoff (I forget his name) seemed more like a plot device than a character, the Superman and Batman are gay lovers twist could've been interesting if they showed how it affects Knight Hawk, but it instead is used only in service to Marvelous Man's affair with Mind Master. Awesome Man being revealed to be Little Wing was neat, although I swear I've seen it before, but no effort is put into addressing that Batman got Robin to seduce the Flash. Knight Hawk raising an army to take over the world, though an interesting twist, felt out of place. Cast performs their roles excellently.
TL;DR: The Guardians Of Justice is a show I really wish I could love, and is actually pretty solid before they solve Marvelous Man's death.