I have used it twice now. Here is my so-far review:
Initial Adjustments: You can choose the location (exercise room), the music, and your fitness goals, both in general and on a daily basis. You can earn more rooms to choose from (there is only one to start) and more music. You can choose when you will work out and for how long.
Fitness testing: The testing is pretty elementary and depends on your being honest. You do an activity and then report on your results. For example, you report how many heart beats you count in 10 seconds. You count the number of sit-ups and push-ups you do. There are only a few fitness tests and you can not substitute something different for any of them; but you can skip one if you like.
Variety: The advertising says the program offers over 450 different exercises. But it doesn't actually give you any choices beyond what your fitness level is perceived to be and what your goals are. Your coach chooses the exercises and you follow along. Obviously, the higher your fitness level the more variety you will likely experience. A nice feature is that as each new exercise is coming up you can see it slide into place, so you can be prepared for it.
Adjustment to you: There is no way to factor in any physical disability. I could not note that my knees are bad, for example, and therefore opt out of exercises that require much knee use. During a typical workout, though, the coach occasionally stops to ask how it's going. You can choose from three options, indicating it's a breeze, it's tough, or you can't keep up. Based on what you answer she will adjust the workout the next time. I chose the last option again and again, hoping there might be some change to the exercises. I discovered that I was given more breaks. Actually, that's okay. I can live with it.
My basic take on the program is that it can be useful for a person with no significant physical drawbacks, other than simple lack of strength or endurance. I suspect it can be fun for a person who wants to go all out, pushing her limits, because the program adjusts to what you tell it about how you are doing.
I feel I can use it too, mainly because I am okay with adjusting the motions to fit my body and my limitations. Because I have only used it twice, I do not know how long it will be before it suggests that I do fitness testing again.
I like how it can adjust daily. I can choose to focus on upper body strength one day and I can stop to do a tutorial in the middle of the workout if I do not know how the exercise is done. This sort of feature is much better than a straight video or DVD program. The next day I can go for lower body (I doubt I will ever do that, frankly, but maybe if I feel like modifying, modifying, modifying). If I am feeling extra strong I can work out for a longer period.
It would be improved if it could be coordinated with your body or heartrate directly - so your heartrate can be monitored on the screen, like with an exercycle, for example, and if there were adjustments to the exercises themselves that you could ask for, based on physical disabilities. Another option would be to choose preferential exercises - that way I could avoid those that I simply cannot do. For the price, though, I am certainly not complaining.