Humbolt is awesome from what some good buds have done with it. I have the luxury of space for the few plants I grow for myself on regular basis. You can use them on hydro or soil. From what I have seen on their plants it stops upward growth with a quickness. One friend was upset because it did too good a job! He thought it would slowly stop.
I have considered using it, but with hydro since its typically an indoor grow you can curb verticle growth by stimulating light cycles anyway. Outdoor growers wanting more of a bush than an 8 foot wonder would probably benefit more from bushmaster IMHO.