I spent hours last night (stupidly) trying to figure out how to make SHS give me an exposed filter that would allow me to select a parent term in a hierarchy and show all the children. The documentation only mentions adding a new filter using the term reference field. I noticed in(and before that in ) that SHS adds an option for "Content: Has taxonomy terms (with depth; Simple hierarchical select)"
The documentation should probably reflect this. It's a great feature!