Trick I learned with netflix on a PC - press pause, then ctrl + shift and left-click your mouse on the screen. There's a menu option called stream manager. Choose that and you can choose the rate at which your movie plays. It defaults to 3000, but I play it on 1000-something all the time, uses less bandwidth, *I* don't notice a quality difference, and it doesn't constantly stop to buffer. I don't know how to set this permanently though, I have to change it every movie/episode.
(My ISP has a data cap and we are charged extra if we go over. Choosing a lower whatever-it-is ends up using less of our data)