I do use CC licenses (and dual-license at times).  Relevant to this discussion, it is worth noting that "or later versions" is required, rather than optional, with the current CC-SA licenses.  However, clauses that allow legally binding documents to be unilaterally changed by third parties are always going to make me uncomfortable no matter how many phrases about "similar in spirit" one includes in the text, or how respected the license writers may be.

 

-Robert Rohde