The Nighthawk is a very elegant design, no coupling capacitors in line although here is one electrolytic in the feedback network, so will have some (probably small) influence on the sound.
I think the biggest drawback is that it uses feedback RIAA equalisation, which in most people's opinion, that have heard the difference, results in a slightly compressed or 'sat on' type of sound delivery.

The one overriding quality is that it is VERY quiet