With A/D converters (as with a lot of mic pres, actually) my experience is like this: Play me comparisons between two pieces of gear without any context and I'll be having a hard time telling them apart, let alone pick a definite favorite, sometimes even in a studio environment. However, once you don't just run one signal, but 40+ through them, as you would in the recording of a song, and start mixing them together, the differences become very obvious. Like for example the lead vocals, that you just can't seem to get in front enough, or that you'll not be able to really give the impression of a room.Anyone who can hear the difference between A/D converters should email Mr. Winer with the answers to his test. He uses a (ca 2011) Focusrite 8i6, so it should be easy, right?
I realize that this may seem like me talking about the mojo of my bubinga fretboard or something... It is okay if you don't take my word for it. I am giving advice from my perspective and it is up to the OP if he/she decides to take it or not.