I need my cardio, it keeps me sane. Yes, I understand the benefits of intervals & using weights. There are very few options (as far as fitness dvds go) that can compare to the intensity Amy brings! I end up sweating buckets. After the workout, I feel amazing! It's an endorphine rush, and I am a total addict =) Highly recommend this for those looking for an intense cardio workout!!There is a bosu (dome) workout out on the dvd. For those that don't have a bosu - there is a modifier and she uses a step. It may not be as long, but it is intense. Your legs/glutes will feel the burn, and good luck walking after ;)The only drawback is the choreography. The first couple of times you do the workout, some moves may frustrate you. You will get the hang of it, be patient, it's worth it!