As far as an actual work out. Wii fit wasn't that effective for me.

As far as accountability, best thing I've ever tried. Wii measures you when you step on the board. If you don't weigh yourself one day, you can't go back. It got me to weigh myself everyday and make better food choices because I knew the very next day I would be weighing myself. The only problem I have with wii fit I've never been able to get it to work right on carpet. I have to use it on tile floor to any kind of accurate readings. There are adapters out there for if you have carpet but I've just never been able to get it to work correctly. But if that's not an issue. Simply for accountability (and balance, it has improved my balance as well) I recommend Wii Fit.

It is exercise so try it. I had friend who did the Wii tennis and lost 40 pounds in 3 months.
I don't know if it is on the Wii Fit but I would still do the Wii Fit if I already had it. Maybe supplement it with walking or weights.
Oh, heck, GO FOR IT!

My family has Wii fit. I once did all wii fit for two weeks, though fun and challenging, it doesn't beat a regular work out routine.

I got the Wii Fit for Christmas this year and have only used it a few times. I did not like it that it blew me up to a bubble girl when I weighed. That was not very motivating at all. My husband only had a few pounds to lose and it shows him the same bubble size as me. I haven't tried any of the other games but my brother just gave me some to try so I will do that today. I think the dancing one was one of them.

It's fun for a while, and motivating-ish.
When we got ours, we used it a lot - though I do agree with the above poster, that the scolding, crying avatars, and bubble sizes aren't exactly motivating. I really enjoy the Gold's Gym Cardio Boxing game, though. I probably got a better workout from that, than I did with Wii Fit/Fit Plus.

If you're a very beginner - go for it. It may be worth it just for the kick in the pants and novelty, potentially spurring you to do more in other areas. Who knows?
I'm of the belief that any novelty is worth it, even for short term benefits. Whatever motivates you in that moment.

Then again, if you can't think of another use for the Wii besides this, maybe not a good investment - since it IS expensive.
We play other games on it, too. So it has been worth it in the long run.

I do think about playing the games occasionally still, but only for entertainment. I don't count it as exercise unless I'm doing one of the more involved games(not the Fit/Fit Plus).

It depends on your fitness level and what you're looking for it to do long term.

I look to the Wii itself as a good investment. The Wii Fit/Fit Plus is a good game, but not a huge exercise benefit.
OTHER Wii fitness games have been great, however.

The Fit/Fit Plus is OK, with yoga and the balance games being the best use of the board. Cardio is not great... just step and walking/running workouts. Strength is a joke, IMO. And, as others have mentioned, the system nags you constantly. You can't miss a day without getting a lecture... you even get a scolding if you work out at a different time of day. Annoying.

If you're looking for a good sweat try the two Gold's Gym Cardio/Dance workouts. I also really enjoy Just Dance and Michael Jackson Experience.

Love it and it works!

I use the wii as my daily exercise with the wii fit board, as I have hardly no exercise while at work.
30 min every morning either my wii routine or a jog and have lost some weight so far.

Although I have combined this also with healthy eating.

They really need to fix this. It is a big problem for kids. It doesn't bother me too much but my young girls are upset by that feature.

I think Wii Fit is a good intro if you haven't been working out at all. But as you get more fit, you'll probably want to progress to other programs that are a little more intense. I'm just starting up again after not doing anything more than walking for a while, and I can get in a good work out with the Wii Fit (really work up a sweat and get my heart rate going) but I know in 3-4 months, it will be more for fun than for hard exercise. However, I do think it's fun to play the games and it's still better than just sitting around. My 7 year old loves to play the games too, so we will use it a lot over the winter when we can't get outside as much.

I love the Golds Gym Cardio (boxing) that wurdnerd mentioned. I just got the Golds Gym Dance one but haven't had a chance to try it yet, so glad to hear it gets a good recommendation.

I actually really like using this for while I do other things. The aerobics workouts I find I can do while listening to books on audio, so I can do my textbook reading while burning off a few calories. You can also do it when your favorite show comes on, so you can watch TV while stepping instead of snacking. It's kind of useless for just normal working out though. Don't replace a gym with it.

During my weight loss i played alot of Wii tenis, boxing and stuff with friends. It should not replace any sort of traning but it helps you move around in a fun way. For me it never feelt like traning, feelt like playing videogame and have fun. The movement and energy burning was just a bonus.

LOVE the wii fit and love the wii sports games, tennis is my favorite and it gets me and the whole family moving we are no longer fat couch potatoes after dinner now we play tennis for up to 2hrs after we eat then get ready for bed for the night. EVERYONE has dropped weight since we got a wii- not the ones you sit on your rump with that feeds laziness but the ones that you physically have to stand and move.

Have it, worth it but for fun. I do a lot of walking and dvd's and the Wii is just for fun...the Dance ones are awesome, burn a lot of calories, sweat and have fun! Just something to get us off the couch.

I have Wii fit +, golds gym cardio, just dance 1&2, and My fitness coach

On Wii fit + I like to do the free run, I use my bosu like a step and watch tv while the Wii keeps track of the time. I can get a good work out then. Most of the time I just play some of the silly games and I like the yoga and general exercises. It does keep good records of your weight for the last year and you can see your progess.

Biggest loser on the xbox kinect! You get sore!!