Boards
Spirits-35ml measures: For or Against?
I suppose the argument is largely academic in that most every pub seems to have adopted this as their default measure, but, nonetheless.........
Upside: More for your money, negates the urge to order a double (which in old money would almost be a triple) thereby saving you money/headaches.
Downside: The feeling that a single isn't quite enough, but, a double is a little to much.