Some observations. I listen to Spotify, and with Waves Nx active the sound is brighter and doesn't appear to come from inside my head, which is where it normally resides with headphones. With my USB camera in place, Nx detects my head position and alters the sound so that it appears to remain in one spot even when I turn my head. Technically impressive. But I'm still trying to decide if it's an advantage. Do I really need to pretend that the music comes from a spot on my desk, or am I happy to have the sound remain the same when I turn to look out the window? It's easy to turn off this feature, so you get to decide.
I'm used to running audio through Audio Hijack, mostly for its great equalizer, but Nx doesn't work well with Hijack in the mix. This isn't too surprising, but without the equalizer I lose the exaggerated bass that I prefer.
I'm running the 30 day trail of Nx, and I'm not sure I'll buy it, mostly because of the lack of an equalizer, but for $10 bucks, it seems a good deal.