I've read somewhere that Hilton Gold is equivalent to SPG Platinum.
There's some merit to that - SPG Gold doesn't quite cut it any more for me other than the 4pm late checkouts and the wider selection of hotels available to suit varying budgets.
Hilton Gold offers free breakfast for 2, complimentary high speed internet access and executive lounge access which means - free drinks, cocktail food, wifi yada yada.
And I really dig the fact that my account with Hilton Honors is updated very promptly without my having to write in to check on the status of my points.
I think that I will focus on keeping my Hilton Gold membership and possibly give up my SPG one.