All of my ASIO drivers have worked great with PT. even my apparently native Behri USB 202, which I use for turntable/cassette captures, works amazingly well. I find little/no difference between PTPA and other DAWS (and I have a scad of PC-based ones installed). That being said, I don't have any direct experience with the new Vox USB AmPlugs. I'm guessing they're more interface than headphone amp. I would assume that it would have to come with amp/cab/efx plugins to be competitive with other offerings---does it?
I do have the standard Vox Acoustic AmPlug which I give a lot of use because it is a convenient practice tool and it does it's two sounds (clean and acoustic sim) reasonably well, with a minimal amount of hardware and wire.

Paj
8^)