Benefits of MF V-Link with a Mac-based system?

I don't think the Rega DAC is asynchronous via USB. This means The Rega's clocks depend upon the timing coming from the laptop. PC guys like myself don't have an optical option when going out to a DAC from a laptop, so asynchronous USB is the way to go, because this means the clock coming from the laptop is trashed and the signal gets re-clocked. The MF Vlink gets us there. My PC-Audio vis USB was improved with the Vlink, vs. going straight to my Digital Link III's USB input. You are using optical, so maybe the point is moot for you, I don't know, my laptop doesn't have optical output...
Some folks will say that the optical connection is more jitter prone, because of the conversion to pulses of light, and how that creates timing errors. I tested optical vs. coax on my little 2-channel system and could not tell a difference, either going from my changer out to the DAC or from my Vlink out to the DAC. I am using Wireworld and Lifatec cables.
The only way to really tell if your SQ is improved is to buy a MuFi Vlink on Audio Advisor for $90 and test it out.
Another thing. If you are using iTunes to play your music, consider getting either Amarra or Pure Music. iTunes does not provide a very good output signal for computer-based audio.

No, I think I wrote in my post above, I cannot hear significant differences between the Wireworld coax and the Lifatec optical cables, whether the transport is my Denon changer or my laptop and the Vlink.
Keep in mind that the laptop-Jplay-Vlink combo can beat my changer's sound quality as a transport, but I found no difference out of the Vlink when swapping cables.
The biggest sonic improvement happened when I DAC'd the changer. Then I wanted to go USB into the DAC, so I could run my entire collection from an iPad, and the USB on my DL III was not as good as the sound coming from my CD changer. So that is when I purchased Jplay and the Vlink. Now the sound is better, but not by much, it's a subtle improvement. If I wasn't using my work laptop, and had to buy a laptop *just* for PC audio, I'd probably say the money wasn't worth the sound upgrade. That would almost double my PC audio investment, and I'd rather put that much dough into new speakers.