I've started exercising using the Wii Fit Plus (I'm not sure where the plus comes from). So far, so good. It's interesting to use and the activities are short enough to where I don't get bored. The last bit is very important because (for me) exercising indoors gets pretty boring and I get tired of doing the same thing over and over again. (Running outdoors is not the same because at least then the scenery changes and the Dixie Dog is an interesting running partner.) However, there are two things that I dislike (1) based on your weight it generates what it (the wii) thinks your body type must be and (2) when I don't do well at some activity it shows my Mii (it's an avatar you create) weeping. Trust me, while I may dislike being hit with a wrecking ball and thrown off the floating raft, I'm not spilling any tears here. I save those for crappy experiments.
(That's not me in the picture. And this person is doing much better than I was earlier today!)