I did some research on my own as I am currently applying to these "hacker accelerators." I think that Hacker School is unique in its lack of structure. This is the second article I have read in which a Hacker School fellow has compared their experience to grad school.
Most of the programs here in the Bay (HackReactor in SF, Hacker Dojo in the Valley) are actually schools where there is a set curriculum in order to prepare you for the workplace.