well, i would think that the bubble hash would be more pure, atleast by volume, most of what you get through that is just pulverized trichs and the hairs, whereas butter just cooks the thc out, along with the other elements of MJ that come out in the butter, like the chlorphyll, which makes it green. So you would need more butter in most instances than you would hash, but they overall would have a similar amount of MJ if they were prepared to be such. It is like comparing apples and oranges.