I have enjoyed the Wii Fit almost exclusively for the entertainment I get from watching others work out. Of course it is a lot of fun to do it myself, but nothing like watching other people.
I personally enjoy the step aerobics. Most people would probably say it isn't too difficult, but I am rhythmically challenged. I do play the bass guitar, but that requires rhythm in your fingers. I am completely unable to coordinate my body to do what I want it to do. I am not what you would call "body smart." In fact, I am "body challenged" if there is such a thing. The step aerobics are great because it is challenging at just the right level for me. Now, the advanced boxing--forget it! I am always stepping forward when I should be stepping backwards, punching with my left when I should punch with my right...Oh, it is exhausting just concentrating to do the Wii Boxing. (Yet, I am compelled to try again and again!)
Perhaps the most fun is the Hula Hoop exercise. I don't do it too often because I'm completely out of shape and it is really difficult to do more than one or two times in a row. That, and you're working out muscles that you don't normally work out!
If you haven't seen someone do the Wii Fit Hula Hoop exercise before, you may want to check out this You Tube video which I think looks a lot like Mr. Bean looks when he Hulas. He is tall and lanky just like the kid in this video.
When you haven't worked out in awhile, your Mii (the alter ego of yourself that you create as your user profile in the Wii games) starts to dose off while in the Mii Plaza (aka waiting room) of Wii Fit. Since I've been fairly regular about working out with the Wii Fit, I enjoy watching everyone else's Wiis dose off. I told Mr. Bean his had fallen asleep and he decided he needed to Wii tonight.
I've seen a lot of strange, large circular motions with the lower half of Mr. Bean's body and long arms flailing (don't get too close!) this evening.