I've received one of those Barrel knockoffs in a trade bundle before. By principle I would never buy a knockoff and especially this one. The UI was a mess and the inner sleeve was supposed to be removable to allow for 16340 use. However the thing was practically press fit into the outer housing and impossible to remove. Even if I could remove it, the battery would be visible from the cheese grater holes, thus completely vulnerable to any moisture. It also raised the question of if the light with the sleeve was water resistant at all.
Maybe they updated some features, but a knockoff is still a knockoff.