I don't pretend to know anything about how the Mason's operate, but this whole 'preferential treatment' argument seems a bit dull.
We all judge people, rightly or wrongly, on their backgrounds, their life and work experiences (else why else have a CV?). IF (IFIFIFIFIF) it happens, I can't see what is wrong with taking membership of a organisation that does huge amounts of charity work, with the associated sacrifice of time and money, into account.
It seems a lot more honest to me than the 'Old school Network, or relying on one's London Club membership or Daddy's money to get a job. Only difference is Masons can come from any background and I beleive that the only 'general' criteria for joining (if one joins!) is that members should believe in a 'higher being'. I don't, which is why I have never taken my interest further.
As I said, if I am talking rubbish, I apologise to the Masons on the thread, but it just gets on my t**s when everyone wants to know everyone else's business, basing their justification on rumour and conjucture.
Shutting up now.