I love circuit tapes, too!  Why does it seem like there aren't very many of them out there?  Circuit Max is awesome!  Anyway, I just wanted to tell you that I've been reading a lot of reviews trying to find a good one...I read in the New Reviews section on the VF site that Energy Action Circuit by Mindy M is a good workout, but I don't have it.  I just bought Gin Miller's Circuit Challenge (Reebok), but haven't tried it yet.  I'll let you know what I think about it.  If you go to the VF Discussion Forum, I posted a thread asking for suggestions on circuit tapes, and a few people responded with comments. Sorry that I couldn't help more at this time!  Please let me know what else you find out!
Thanks,
Heather