Get a compac from sidehack and novak the Gekko fellas before getting a U3. My opinion is it is a much better product, you cnanot beat the price of $25.00 and the support here on the forum is fantastic. I have 5 and at the moment my best 3 shares showing are 17.9m, 27.1m, and 11.3.77m which I hope is 11 billion and just happens to be the way it is displayed in cgminer, but not sure.
I just enjoy tinkering with anything fun, and almost anything with power running through it and a flashing light is killa fun. It doesn't beat sex, but it is a great way to spend time while you recharge