Amy: are you already doing Cathe?
I haven't done this series, but I have a friend who has it. She did lose a lot of weight on it (also drastically changed her eating habits), so I asked to see the workouts... I was not really impressed. They were okay, but if you are used to Cathe, you will find them much less complex and interesting. Also, there is little variety. I believe you are also pretty much doing the same workout six days a week.... (you do a beginner's workout for a couple of weeks, an intermediate, then an "advanced").
I was not very impressed, so I lent her KPC/L&G. }( }(
I think anything can work if you stick with it and clean up your diet. But is it fun and motivating, that is the bigger question...
Good luck! Let us know what you decide to do.
Marie