I bought the whole set. I've tried a couple of them (1 and 4), and to be honest, they stop and start to often to be a really good consistent workout. The 4th one is only 15 minutes long, and the 3rd one seems to involve aerobic moves like taking down your hair and tossing your glasses
From what I've heard, the second one is supposed to be a very good workout, but it's not a stripping workout.
For a good dancing workout, I have a Tahitian Cardio DVD. That makes me sweat and makes my thighs burn!