I ended up getting the remote control volume option (super handy and smooth), but not the relay volume.
I did compare the relay v.s. pot option, but frankly I couldn't tell them apart. The main reason why I went with the remote pot option was because the relay felt very clunky and not very nice to operate. Whenever I adjusted the volume, the distinct jumps in volume were felt as "blip" sound, which was quite annoying. I guess it's nice that V281 gives you the option for one or the other.
The internal DAC module for the V281 felt quite outdated and "off the shelf" design. I was a bit disappointed when I looked at it, because it is pretty basic with not much going for it, in terms of USB isolation, reclocking, jitter reduction, D/A, I/V etc. The sound is very straightforward and clean. Nothing wrong with it but other external DACs could bring out more from the V281 amp.
S/PDIF and USB DACs from other companies have moved on a long way over the past few years, not just the D/A chip itself (ESS, AKM, whatever), but in terms of care and attention put in to ensure the data and power input is as clean as possible. The add-on DAC module for V281 doesn't live in this day and age, so I am hoping that Violectric can release some modern up-to-date DAC modules to keep up to date.
I'm currently using an iFi micro iDAC2 to go with the V281, because it sounded nice to my ears.