I'm sorry but given the "night and day" differences we know that the placebo effect is capable of making people swear by for things that turn out to not have any effect at all (often to little surprise to some) this testimony is hardly convincing...
I'm with you.
I'm in the camp of 'it makes no difference'.
However, the test i did (at the behest of the system tech) did make a _difference_, but didn't make it better or worse, just different. Now, judging by the posted results of the SFL test, what may have been heard was an increase in jitter, but again, it was different (read carefully: not better, not improved, just different).
My point was mainly to illustrate the fact that most people have an opinion, without performing any testing.
I am fully aware of the placebo effect, the only reason i ruled it out here was because there were 2 engineers listening during the switch that weren't aware of the testing being done, and they commented on a difference, So much less likely to have an influence there.
Anyway, its interesting stuff, but i certainly advocate the point of view that there is no improvement to be had, and that if you want to improve things, you need better converters...