I have no problem with any kind of music selection as far as SET amps are concerned. If they are paired with suitable speakers, they can deliver clarity, detail, weight, and do everything quite well. But, they are considerably harder to match with speakers, given their low output and quite high output impedance than a pushpull amp, and probably harder than an OTL given how low the output of most SETs (an issue for me because I prefer the 45 and 2a3 tube over 300b or 211 or 845). But, I also agree that most of the lower priced models do not deliver the goods--it really does take high quality output transformers to get decent SET sound and that does not come cheap. I've heard a few of the supposed giant killers and the sound of these tend to be quite bad--anemic, dead and too light weight-- in the setups I heard (perhaps the amps would have sounded better with easier loads).
OTLs are no different from other amps--each implementation/tube type sounds different. Atmasphere and Joule OTLs, for example, sound very different and which is "better" is a matter of taste.
OTLs are no different from other amps--each implementation/tube type sounds different. Atmasphere and Joule OTLs, for example, sound very different and which is "better" is a matter of taste.