I wear a heart rate monitor for every physical activity so of course this too. Ive bought EVERY music pack available over the course of 2 years and yeah probably spent a bit, but $12 a month (now wont have to pay unless they drop something else) is worth it to get me up and active. I play a song until Ive gotten "SS" rank (Hard) then move onto the next song. I burn ~400-700 calories per 1-1.5 hour session. To put things in perspective I burn ~300 on a 1 hour/3 mile dog walk in the morning. Im dropping weight like CRAZY,, and while this isnt the ONLY contributing factor for that, it accounts for a LARGE amount of the calories I burn in a day. Not to mention the hand eye coordination training as you have to move each hand at different intervals and directions. Its not a game for me...its a lifestyle choice. Lol