As said above the British forces are very much in the minority using QFE however some parts of the opperation are very high workload such as IF approaches in a fast jet or SH. In these conditions I can see QFE being a distinct advantage, the rest of the airforce, army & navy follows the just to keep SOP at military airfields.
This may have to change as more modern aircraft come into service as QFE may well not be compatable with the aircraft systems. For this reason you cant use QFE on the Boeing 737NG as setting QFE feeds errors into the EGPWS.