watts are watts, a watt will do the same work regardless of how its derived.
amp topology, power supply type, amount of components in the circuit, speaker efficiencies, etc. will make differences. as long as your not clipping the amp, putting the amp into harm i.e. oscillating, etc. should all be similar as far as power requirements for a given speaker. Probably much lower then most would like to admit.
Bragging rights, power wars, room size and volume, etc. seem to be more an issue. don't get me started on "oh its hi current" well of course, because its low voltage. Power=Current x Voltage after all.