No, it's not safe! It will make you skinny and shun chocolate! Anything that does that is purely evil in my books.
They actually work but you need to be motivated. In tems of fitness, I much prefer EA's Active which is less Nintendo cartoon fun and more serious. Just be careful not to strain yourself, I was sore for days afterwards... thinking I was a man and playing it on medium level!
Yes, I agree, Wii Active is more serious at improving fitness levels that the Wii fit.
Has anyone bought any of the other Wii exercise games? I have the Jillian Armstrong one I find very basic and quite boring. I have also tried the weights (that you attach to the remote). They seem to interfer with the signal and the system doesn't seem to detect my movements... very frustrating