I didn't like the sound, but since everyone else here seems to love it, I suppose it's just a matter of taste. I found it unnatural: the smallest correction quickly made the sound sound tweaked.
The build quality felt inferior to most series 500 modules. Just considering weight, it's the lightest module I've had in my hands. The tiny knobs felt flimsy in my hand too. I suppose it's still sturdy enough, but I see why this one is much cheaper than the API or Neve equivalent. In that regard, you can't complain.