Found this pretty good lag fix for Twitch. So far, I've been able to watch Getawhale's stream when before I could barely watch Low or Mobile (and forget about even loading Source! That almost never happened).

http://www.reddit.com/r/Twitch/comments/26s9y7/im_developing_software_to_stop_lagbuffering/

Hope it works for anyone else having problems (which is always a lot of people).