I play all kinds of music on my Super Zen/Omega combos, and have never run out of power. There is the odd amp out there that could be called a giant killer and any vintage of the SE84 are giant killers, in both sound and build. It isn't outclassed by any speaker it has the power to drive, regardless of the price of that speaker. As good as your Fleawatt is at $200, the SE84UFO is in a different class altogether. The Wolf Ear Kitoki is also in the same class as the Decware. I love good solid state, but my main event is still the flea powered SET - has been for going on seven years.
Where Class D beats most is, if like me, you live in a warm climate with long hot summers. The Fleawatt, NuPrime, Temple etc. Class D amps IMO are the "go to" amps in the heat. Class D would be useless if it didn't sound good, but good class D does sound good - it's come along way.