It's a long dynamic tension set. Basically, it's 21 movements, of which you start with the first 3, and then add three more each week until you're at 21. You start the reps at 12, and then once you're doing all 21 movements, you increase the reps by 1 rep per movement per week until you're at 36 reps. Make sense?
Sifu Allen, the guy who demonstrates it on the tape, is a fairly large guy, but I wonder if all his size comes from stone warrior. When I did it i didn't really gain any size (aside from in my shoulders), but you can expect increased muscular endurance and hardness, if you practise it for a while.
All the movements directly translate into fighting applications, and Green Dragon claims that this will build strength through the fighting motions. Makes sense.
However, I have recently come across research that says that even if dynamic tension exercises are practised, one still needs to occasionally lift heavy weights so the nervous system will become accustomed to the stress as well. (power to the people - pavel tsatsouline).
If you have the money, it's worth a try. The only thing is some of the movements on the tape he demonstrates, he only does them on one side. Always split everything up, x on this side, x on that side, otherwise you will look and perform lopsided. After all, you wouldn't train your left bicep more than your right, would you? Excatly. Split everything up evenly.