There's an old thread about this from a while back.  It's a good starting point:

http://www.theeroticreview.com/discussion_boards/viewmsg.asp?MessageID=16264&boardID=11&page=#16264

In general, the concensus opinion of most folks is that Mitchell Brothers is the best.  MBOT is basically a world famous, San Francisco institution.   http://www.ofarrell.com/home.html   Been there many times through the years and it never fails to impress.  However, it is (like all SF clubs) very expensive.  You will burn through a lot of money quickly when ordering private services.

There is a plethora of well known, very good gentleman clubs in the City.  You can check them out at various websites like TUSCL -  https://www.tuscl.net/c.php?CID=1393

IMHO, the clubs are a lot of fun, but for the money you drop at these places, I personally think it's better to spend time with a great escort, of which San Francisco offers many.  Come to think of it, some of my best expereinces at MBOT have been when I was accompanied by an ATF  - that turned out to be money well spent.

Good luck with your visit .....

SFG