I don't know whether the deterioration in SQ, when using an adapter, is so great that you would notice it, or not.
My personal preference would be to get one with the standard 1/4" plug. A new one is not that much more expensive - about $125, I think. And... I've known others who upgraded their cable to the 1/4" plug from the combo 1/8 to 1/4 plug, for that reason.
While I think the Headphile Senn v2 is a good cable, I think I would prefer a Silver Dragon v2, or RAL Cryo Silver (with black cover, not the pink cover) - these both look like much more substantial cables, and I suspect they sound better also. Unfortunately... they're much more expensive.
I'm thinking of upgrading from the Senn v2 Black Silver for that reason.