I enjoy Amy's Advanced Step Challenge. I do agree with Karin that you really should walk through the video on an 4" step - especially until you get the crazy shuffle down. It's a blast once you get it, though. It's not an easy step workout, but if you got Rhythmic Step or Step Blast fairly quickly, you'll be okay. It is FAST! I noticed the whooping more during the preview than I do when I working out to it, mainly because I'm concentrating more on not falling on my face. Amy is extremely high energy. I keep glancing at the TV to make sure she hasn't gone into orbit or something. But she gets the heart rate up.
I haven't tried BootCamp yet as I'm doing a P90X rotation, but I've heard that that one is really good, but she rests too long, so if you just fast forward during the rests you'll keep your HR up where it's supposed to be. The intervals on BootCamp and 2 minutes long each, and there is a lot of equipment required. (Dumbbells, barbell, step, stability ball, plates or rags for some functional fitness moves...).