Community feel, adaptability to fitness levels (both to limitations but also to increase difficulty when needed), the workouts are well-rounded (over the course of several workouts I will hit the full body without trying to focus on body parts), support from coaches and staff, and it's fun!!!!
Smart workout that is customizable to ME. Watching my heart rate allows me either push harder or tone down as needed, while still doing the same workout as a super-fit person next to me. Makes me feel good and oh so sore!