I like the YRG stuff. I think it's a distillation of the most useful stuff from yoga. I've actually done YRG off and on for about two years now, having gotten the book in late 2005, and consider it just as good for mobility and flexibility as the dedicated mobility programs you can get. It's been nicely complementary to lifting.
I'm normally somewhat indifferent towards testimonials, but this one impressed me and I thought it was quite cool.