The 8.1 drivers work, if you hack them a bit. I've got my V Studio 700 running perfectly under Windows 10 Pro 64, thanks to folks on this forum. It wasn't all that hard to do, once we knew what to do.
But I'm not comfortable with the idea of using out-dated and hacked drivers -- especially with this particular version of windows, which is going to see regular incremental upgrades that I can't turn off, for the most part (or so I understand, anyway). I can see a situation coming where I'll wake up one fine morning, and my Vstudio 700 interface suddenly won't be stable because Microsoft pushed through some update to the OS that messed up the drivers. You gotta hope for the best, I suppose, but after spending all that money buying the system, I'd expect something better from the manufacturer than to be left in "hope it will still work tomorrow!" mode, especially when we're just a few years into the life of the product.