I've heard both. I really do not think they are comparable. The Vox sounded very nice, but with the usual problems that you get when you "cheat" the size of the mouth of the lower horn (their bass horn is much smaller than just the midbass horn on the U3 that should just go down to 120Hz). It was very rounded and more colored and some might call "musical." The resolution on the whole line was lower and I have no sense of continuity that I did with the U3, the U3 were simply not there. The vox bass / midbass was rather mushy. It was not even close in terms of dynamics and vastness and effortlessly. You can just see by looking at these horns, how much larger the radiating surface area of the U3 is. I also suspect that the U3 are much more efficient. The vox seemed to me closer in the direction of the great JBL or Westlake, not U3. They are beautiful, for sure.