Same here. Twitch is the only media player that frequently cuts out for me when playing 1080. I only caught about 15 minutes of Viper's stream earlier, first time on Mixer and happy to say it didn't buffer on me once. It seems smoother than twitch.
One thing I really don't like is that I went to watch the VOD of the earlier stream but there doesn't seem to be any, unless i'm blind.
It will go here when he sorts it.
EG: