Depends on what you’re looking for in a workout, cardio or strength training. One that has been around for a while is Les Mills Body Training Systems. They offer several different formats which include strength training, cardio interval training, cycling, yoga, dance, and step to name a few. The reason they are so popular is the music and choreography is created by the Les Mills team. They come out with new workouts every three months so the routines never get boring and the members of your club know what to expect when they enter a class.