Is an autoformer (AVC) always superior to pots and resistors ?

I've tried an AVC incorporating Slagle's parts. It sounded dead quiet but my system needs a bit more boost and I like the coloration added by my 6SN7 tube.

Dunno.

I prefer optical comparator, crossing at zero (silent)

The PS Audio gain cell design is superior also.

I can only say I love my Coincident Statement MkII pre with dual transformer volume control, superior to any pot or resistor based volume pre I've owned. Absolutely most stable imaging imaginable, no tracking issues whatsoever.

TVCs, ime, rounds things out and softens transients, but like everything else, it is what your ears like. TVCs are supposed to be better with impedance matching between source and amp.

Its all about implementation, no way, no how my system softens transients! In fact transient performance, especially of the micro type are quite incredible. Coincident Statement has likely the most robust power supply I've ever seen in a pre, much more like what you see in power hungry amps.