Again, without knowing what was wrong with your previous system, just telling us it is better tells us it's better than broken, and that's not telling us much. Most of our systems aren't broken.
USB is fine for transferring data -- think about a program, or an encrypted archive: it needs to be a perfect digital replica of itself after being transferred. If one bit is off -- one bit! -- it is considered corrupt.
So the only thing left is timing. Jitter. Jitter just isn't that audible, not as night and day as you are describing. It's subtle, as Sechtdamon says. Not unless something was really really wrong, and you should have been able to hear a difference just by trying a third system.
Look, I'm happy for you that it's so much better than your old system, but most of us wouldn't have put up with that shit.