If you are a cardio junkie and you don't mind compilations, CF is a good purchase. If you can wait until Cathe's new DVDs come out, you might be able to get free shipping if you order her new series.
It is SOOO worth it! There are premix's (the 80 minute one is too long for me) but I love the shorter ones and the original program. It is just hard enough, not so much you feel totally wiped at the end.