Not a workout, but it is good for a laugh
First and foremost, Wii Fit is a video game, not a workout video. If you're looking for a game to help you lose weight or get in shape, you should be looking at Yourself! Fitness for the original Xbox. Wii Fit will get you off of the couch, but only in short bursts.
There are various exercises that you can perform in Wii Fit - from Yoga to muscle to cardio to balance games. No matter which group you select, you can only perform one exercise at a time. The problem here, is that, instead of being able to select several exercises to make a mini-workout, you have to select one, do it, then navigate through some menus again before beginning the next exercise. This works for the balance games, because you're not trying to break a sweat, however, when performing the muscle or cardio style exercises, it really would be nice to queue up a bunch so you don't have to stop in between.
Bottom line:
Wii Fit is a fun game for the first few minutes. If you're looking for a good workout, go elsewhere (like a gym). If you're looking for another party-style game that makes all your friends look goofy, then it might be worth checking out.
