The grains are much better than the powdered starter. Plus, they are infinitely less expensive.
I'm not sure if the instant digestion is completely why the fermented juice is so powerful, but I'm sure it has a lot to do with it. I believe some amazing compounds are made by the grains that just boost the hell out of the immune system and energy producing capabilities of the cells.
Whatever the case, I'll just sit back, relax, and enjoy.