Really more of an improvement to Wii Fit but still good
The challenges, sports and just the new features especially are very good and fun. There are better motivation ways. Such as trophies. There is also less limitations like a custom goal to achieve and custom workouts. More deatils on yourself and better ways to get fit. And generally more depth in the game.
The bad thing is of the elastic band is to train. It does lack resistance and is quite awkward to use. Anything is the longevity, no more routines once done or online mode. It's probablary the main problem of fitness games, you WILL eventually get bored.
But still the good thing is that at least it actually want you to use it. I cannot actually say that it's better than Wii Fit however what I can say it is a great fitness game.