I love having my WiiFit Plus for the days I simply can't get out to do any other kind of exercise. Doing it regularly is key, but even sporadically for enough time in one session is good too. They have a mix of different kinds of exercises to work different goals. Usually I'll hit up a bunch of the strength training ones, mix in some yoga, do a bunch of balance games and one or two of the aerobics games.
When I use it regularly, I really notice how strong parts of my body (like my calves from the ski jump game) get as well as my overall balance due to that strength.
Next on my list is to get some other games that are more geared toward cardio because WiiFit does lack a little in that area. I tried Just Dance recently and that really gets your whole body moving.
In summation: do it if you can afford it.
| current weight: 150.0