I've been suffering from guilt that my Yamuna balls have been collecting dust of late.
I have some of the DVD's, the black, gold and pearl balls and went to several workshops some years back when we had a teacher in the area. Unfortunately she's moved away.
I strongly prefer Yamuna balls to foam rollers. I find foam rolling to be sensational in a frequently overwhelming way. You can adjust the amount of air in the balls to suit your body.
What I need to do is use the DVD's, write down the specific exercises that I want to focus on and just do those versus trying to do the DVD's. The DVD's are well done, but they're like a class or workshop, and run longer than I have if I'm going to use the balls consistently.