ryzmom - Yes. Jillian likes to combine cardio with strength training because it's more effective. I haven't done NMTZ or BFBM but I've been working my way through 30DS and it's intense, non-stop circuit training for 20 minutes. 3 minutes strength, 2 minutes cardio, 1 minute abs, three times. It's awesome. I'm sure she incorporates cardio into the other two workouts as well, but I'm not positive.
Manda - Sounds like fun... in a, omg I'm gonna die kinda way.
I'm up for the challenge, definitely. But first I want to get through 30DS. I'm halfway there!
I also just bought her Yoga Meltdown which I'm scared of but also looking forward to trying out.