Al, I LOVE my bosu. It's wonderful. I have several bosu specific workouts (some made by the company that makes the piece). There are others that use it, ie Awesome Strength with Mindy Mylrea. Then there are some that I modify to use the bosu---basically easier step workouts like Step It Strong with Keli Roberts. Not easier in intensity, but less dancy.
I feel that it works my legs harder than a step, and the core is worked a lot more too. I recommend it!