Respectfully, Greg has made many modifications to the Tascam. Greg’s modifications include, among other things, no capacitors in the output stage; no amplification of any DC in the preamp from one gain stage to another; new pure copper circuit boards; audiophile grade power transformers; custom designed outboard power supply option; Cardas silver solder for all electronic connections; solid silver grounding configuration to enhance grounding and reduce noise; direct IEC equalization stage; no muting circuits for shortest signal paths; and a dual-mono configuration for the internal playback preamp.
I fully appreciate that the people who own Studers love them for very valid reasons -- and I agree with those reasons. People who have UHA decks love them, too, for very valid reasons -- and I agree with those reasons, too.
I have to assume that no transport mechanism will be more gentle on the tape than the transport of an A820.
I have not yet found anyone who has done a careful, leisurely, side-by-side listening comparison of a Studer with a UHA. Until someone has both machines in the same room in the same system and can compare them using familiar music I think that statements about the sonic differences between a Studer and a UHA will remain merely educated guesses.