Quoting LolaMcKitten:" Ohhh! You will like it!!! I love my Wii for workouts! Start at 15 minutes and slowly work your way up from there. You ahve to start slow or you will be kicking yourself."
If you haven't been working out already jumping right into doing it an hour a day is going to kill you, and your way more likely to give up. So start easy, and work your way up.
I love the just dance games they are so much fun, even more fun to do with others, I suggest a work out buddy! I do it with my SIL and MIL.