Yield seems much better. Im pretty sure it was tested and in comparison it was much more potent, but I dont remember numbers or link (maybe dagger can say).
Think about it. When you soak, as the alkaloids fill up the liquid, it also slows down how much the alkaloids still in the plant will 'want' to get out (like in osmosis, how the osmotic gradient, the difference between concentration of a specific particle in the liquids, will influence the speed of its diffusion). While in the THP, what happens is there is a constant flux of fresh water with no alkaloids, running through, so the alkaloids are always tending to diffuse fast.
Does the explanation make sense?