Thanks to all who have responded, much appreciated. I'm still hopeful that someone out there with "ears on" experience with the Axis will be able to give me some comparative sense of the Axis' sound quality versus the current field of "contenders". It may be that I'm still very well situated with the Axis and that'd be swell. If investing in a more current design can reap tangible sonic benefits at comparatively reasonable expense, count me in! My "evolution" in USB cables, all providing noticeable gains in SQ:
"office" USB > Wireworld Starlight > Locus Polestar > Locus Axis > ???
"office" USB > Wireworld Starlight > Locus Polestar > Locus Axis > ???