There's expensive to test and there's expensive to test. I'd love to experiment with the drop rates from the SC spheres and see how likely you are to get various items from them, but obviously that's going to be expensive. Much as I think it should be mapped, I can't afford to actually do this since it's real money. If I could buy them with in-game gold, it would be a different matter. Does anyone have much idea of how likely you are to get certain items from those spheres?
Also, I seem to remember hearing that you get the full avatar set from those spheres (assuming you get it). Is that true? Also, is it easy to get?