We got one for JimJr for Christmas and hoped it would help kick start us into doing some exercise again. I've done nothing since I packed in cricket two years ago and I am definitely overweight now.
I have to say it seems pretty good fun and has lots of different types of exercises to play at. I tried some and the trainer would say how fantastic my balance is, then I'd try something different and my balance was useless.
Anyway, as we are all being honest my body test said I was overweight (agreed) - about halfway between ideal and obese (probably a 4 stone spread so no arguing from me) and my Wii age came out twice at 53 (which is real +2) and once at 58
I won't read too much into the BMI thing but it is a good indicator of progress and I've edged it down by >0.5 since NYE.