I think one important issue is how these managers, who's roles and titles were diminished with this holacracy approach, will sell themselves as managers in future roles outside of Zappos.

These days no one really envisions working for the same company for 30 years. It will be tough for leaders within Zappos to show on paper their leadership progression.

I think the idea of holacracy has legs, but I haven't seen any other implementation that would lend credence so far.