My wife bought the plus as well. Too early to tell any results, she just started last night. Now I have a sister-n-law that loves hers and claims to have lost a few pounds already. She's had it since Christmas.
I read another article/study (can't access it anymore) that showed how poorly the Wii Fit compares to almost any workout DVD/in-home exercise regimen for burning calories. It basically stated that if the Wii Fit is what it takes to get you to move your body, that's great. But if you really want to lose weight, enhance fitness and stamina, you should try something else.
I was thinking that a GREAT way to burn calories would be if I could get some pedals from like an exercise bike and just use those while I sit down and play a game. That way there's always a part of my body moving while I sit down.
EA Sports Active is much more effective, but WiiFit is great for stuff like the 30 minute free stepping. You can start it, then flip to a recorded show or something and it will keep beeping on the wiimote to keep your rhythm.
We also have one that we bought a few weeks ago. The kids love the games but I can't stand the "cuteness" of the game. It just takes sooooo long to get started. They need an A.D.D. mode. Hit start..pick your person. Boom...pick an activity..boom..it weighs you in two seconds and moves on to the activity. I don't want to have to keep pressing through a bunch of screens. Just let me play as quickly as possible. If I want to see my weight I'll go look at it..The first time it went through and did things was cute, but it gets OLD real quick.
It would be kinda like putting on an exercise video but yet it sits there and makes you read the screen through a bunch of junk for 5 minutes before you can work out. It makes me not want to use it.