I'm using a pair of SM-70 Pro's that I like, but I don't recommend them for single-ended use...balanced yes, but not single-ended...something in the way the circuitry is set up during single-ended makes them 'overload' (DC only) a bit, less transparent that way. Otherwise they are quite good, but no one will likely accuse them of having the best soundstage traits of an SET (single-ended triode) or a good class D (if you can settle on whatever *that* is), but still quite good. Nice dynamic range, nice tone and harmonics (a tad warmish, but ok)...outstanding timbre. Haven't heard AVA, but I know they have their fans, too.
I should add, these, too, are very musical, forgiving amps. Around $400 ea, used.
I should add, these, too, are very musical, forgiving amps. Around $400 ea, used.