Oh the original far exceeds the sequel in every way, but the sequel is more beginner than the original. I don't mean that in a bad way or as a put down towards you or the game, so please don't take it that way (I said the same thing to another person elsewhere and they got offended). If I were to make a suggestion to you it would be to get really familiar with the sequel, how it works, how the exercises work, the flow of it, then slowly transition into the original, because it will kick your tush.
Just as a point of reference, the original is the one I have and I rented the sequel... I am by now means a cardio or exercise expert, but I'm not a DVD exercise noob either, and the original took awhile to get myself used to using, whereas the sequel I really just fell into it quite easily. A lot of people complained that the original was too hard to use and they made a lot of changes for the sequel so that it was just generally easier to use and follow... So while I think the sequel is far more user-friendly, I think the original, hands down, is the better one for exercise and fitness.
The music stinks on both though. Thank goodness for the SD slot.
The one for the DS though, like I said... Worthless trash. There are some things I like and don't like when I buy a game, some games I like more or less than others. The My Fitness Coach for the DS is the first and only game I truly regret getting. Even the pedometer is garbage. I got a pedometer from the dollar store that works better than that one, no lie. Do not waste your time, money, or effort.