Wow, cool thread.
My two penneth' worth: A "sideways" quickstop, as described at the start of the thread, only works really well in a tandem (CH47/Chinook). This kind of supports comments by Nick that the majority of deceleration is produced by the main rotor/rotors.
In any conventional helicopter I would join other commentators on this thread in that a rapid application of a big sideslip is not a nice place to be. Mainly due to potential overstress and also in the event of power loss at low level.
Also don't forget you may experience different low speed handling and engine/rotor governing characteristics depending on which direction you are turning.