Current Nait? Nait 5i or Nait XS?
Whichever current Nait it is (or any other Nait for that matter), it blows the doors off the NAD in most every way. If soundstaging and imaging are everything to you, you may find the NAD better though. The Nait's do a wall of sound, whereas the NAD does more 3D imaging.
APs in general are somewhat easy to drive. I own Yara Evolution bookshelves and love their imaging and soundstaging qualities. Naim pairs up very well IMO, but there's better if you're top priority is imaging. I chose a Bryston B60 as it has a lot of what I liked about the Nait 5i, and is more 3D sounding. Used B60s come up in your price range fairly often.
Had I not bought the B60, I'd have bought a Nait. Truth is, I was about to buy a Nait when I stumbled upon the right B60 for the right price, from the right guy. The B60 has a few more watts, but it's dual mono power supply will most likely have a better grip and control over the speakers than the Nait. That doesn't mean that the Nait is any slouch by any means.
Nait XS is a far better comparison to the B60 IMO.
