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.

In addition to Pure Music and Amarra , put Audirvana Plus 1.2.1 on your list of players to try with Itunes.They all have free trials.I tried them all a few times before getting a solid feel for the differences.They are all pretty good,take your time and audition them.Amarra and PM have more options,choices than Audirvana. I have the MF-V Link ,older version 99.00.I cant say anything bad about it. It seems to work ,sound as good as the Hagerman HagUsb it replaced.Only diff. the HagUsb was limited to 44.1. Have fun!

I used a V-Link between my iMac and a DAC that didn't have optical input so that I could use the coax input on the DAC. That worked well and sounded better than the USB option but I eventually replaced the DAC with one with optical input and no longer needed the V-Link.

The optical to optical sound is better than the previous setup but that's most likely because it's a better DAC. The V-Link works really well if you need it but in your case I doubt there's any advantage to having one.

Many ppl claimed much improved sonics when using V-Link, and especially V-Link 192, with Rega DAC.

To the reasons stated above, I would also add the posibility to play HD files. Rega USB input is limited to standard, 16/48kHz resolution.

V-Link will let you play 24/88 and 24/96 files. V-Link 192 will also play 24/176 and 24/192 files, and will sound much better overall due to tighter specs than the V-Link.