I really like Billy Blanks and his workouts...BUT...if you like symmetry, his workouts are not for you. I cannot do his workouts anymore because he is (most of the time) uneven...For example, he will have you 24 punches on one side, then only 8 on the other. That drives me nuts, but many I am just too anal! HA But, that is why I love Cathe...always even in her counts.
Janis Saffell has some kickboxing workouts that are good. They are not as difficult, but they are fun.
OK, that is my two cents!
jenni