It is always different so I feel that I am exercising all my muscles every week. The trainers will readily adapt an exercise to meet your individual fitness needs. I have a knee injury so when I can't do an exercise, they will substitute another exercise that I can do safely.
I would only recommend it to people who are serious about losing weight and getting fit. It is challenging yet rewarding. You certainly do not waste your time. But you have to be ready for it. I've seen a lot of people try it out and quit because it's too much for them. I do not find it intimidating and I find it extremely rewarding and I don't ever see myself trying anything else, but for other people it may be a bit intimidating .