Brain-Brian,
(this must be a most rare case of you sigining with your name; you are probably not good at it - haha)
I really can't answer your question upon the possible difference in SQ as you posed it. Hopefully others can; I myself am just not geeky enough to find out. What I could softly say though, is that all individual drives seem to matter, without a hint to which is better (they could virtually be the same connected, but still differ in sound). But hopefully 0.9z-7 solves this; not sure (and you will see what I mean when it's there).
2. Is it possible to have multiple external drives on one usb3 hub that appear in XX as one drive letter? If so, can one control which of the external drives is used when ripping?
Ehm, yes-no- ehh -yes.
The latter yes anticipates on the (middle) no because I don't think it is possible to "span" discs over USB (hubs). On the other hand, the first yes says that you can have multiple discs on one USB hub, which makes the answer to the third question obviously yes.
I am not sure whether you can ever get my answer, but to me it looks like the question was not correct. So, might it have been possible to span discs on the USB hub hence make that one volume, then as obviously it would not be possible anymore to address them separately.
Now what ?
Petrus
PS: You said "appear in XX". Well, that can only relate to Galleries I think, and drive letters are not in order there anyway. Furthermore it should be "yes, you can find all under Galleries as a one and the same structure, but I don't see the relation to what you impose by the question, hence how that could be related to ripping. Never mind, but it may urge you to rephrase the question, teach me some better english, or wake up at your side.
Or something.
PPS: Okay ... when I act like *I* have woken up sufficiently, I should interpret (and answer) your question like :
Yes, you can have multiple USB discs on the USB hub (make that USB3 !), and in XX you can make a Gallery of all of them so they appear as one bunch of albums. Next, because they *are* separate drives and volumes, you can rip to each individual you want.