Good implementation of SET amplification can sound astoundingly natural and present, as can OTL (the latter having less 'limitations' as SET with perhaps a 'cooler' presentation for lack of a better descriptor - perhaps it is they are more neutral). The SS amps that I've owned that come the closest to having the qualities you describe have been Bel Canto Ref 1000's. Ultimately I prefer tubes, but the Bel Cantos were very engaging to me.