For those of us who enjoy listening at high volumes, but want a relatively compact, easy to place speaker, I'm not sure there is any choice other than to go dynamic drivers/higher power, and ditto for those who prefer panel speakers. In fact, that's basically my whole concern about low power: it's not the simple, flea-powered amps that bother me in theory, it's how you're limited in the speaker department. I've only ever heard some SET systems playing in a store in passing, and haven't ever really auditioned one. But I have a hard time believing that - outside of large horns (which may have other problems, but what doesn't?) - high-SPL, wide-bandwidth, uncolored, non-resonant performance will be available from an easy-to-drive and easy-to-control ultra-high-efficiency speaker. The laws of physics are against it happening, so I assume that folks happy with their SET systems must be giving up some combination of volume, headroom, extension, neutrality, or clean decay behavior to get their special kicks (some of which are always subject to the suspicion of increased, but pleasing, low-order distortion-induced euphony). I've not properly auditioned Avant-Gardes or the like, and don't have anything against increased efficiency where possible, but it otherwise seems to me that the world's most competent speakers still demand something in the way of clean power to sound most like live music, and I for one am not ready to simply view this as a wattage 'rat-race'. I would love to be proved wrong, and have someone play me a bandwidth- and volume-unlimited SET system that sounds accurate while kicking out the live jams at a handful of watts, but I don't know that I'll ever have the opportunity (or that the speakers needed would fit my house/budget), so I'll stay with what I know works reasonably well.