Wow-I just saw the orinal post, and it was like I wrote it myself. I have a MacMini (not the latest), Rega Dac, Vlink, Pure Music - even down to the Cardas USB cable!
There is no doubt in mind that the Vlink addition to the USB chain was a huge improvement. Not only are clicks and hesitations completely gone, but the the sound has cleaned up dramatically.
I am using coax from the Vlink, but previous posts will make me listen to optical a little closer.
My only question is whether or not the Vlink II is any better, which is capable of 192?