All streamsites are cancer, i don't know why people bother to watch faggots play F2P trash and webcam whores when they could just play the videogames themselves.
I could understand if it was esports but gookshit is boring, arenaFPS is dead and the other good games don't have nearly as many views as some faggot sucking ass at DOTA 2.
Watching your friend stream a game to see his performance or watching a movie with other anons is something else entirely and i don't hold it on the same regard as streamfaggotry.
As for your question, what does Mixer do that Twitch doesn't? Does it have better netcode and servers that aren't ass so you can actually watch content on it? I always had problems with watching anything on Twitch because of the performance issues, mostly because it can NOT understand or account for connection slowdowns or lagspikes, which instantly turn into blackscreens or significant audio delay.