LOVE it. Absolutely love it. Don't get me wrong, the workouts are killer, but in a way that keeps me coming back eagerly without dreading my workout.
I'm actually using the workout to help kick start my fitness post-surgery, and it is definitely working all the muscles that I would have forgotten about. It's a great change from the tedious cardio activities (read: running) that I could so easily have turned to, and keeps challenging new muscle groups.
The actual studios are always very clean, fun, and organized. The owner and instructors are lovely, and add to the positive atmosphere.