What is the best DAC under $2000 and why?

Monarchy NM24 (or the tube only predecessor M24). The NM24 has tube and solid state output stages so you can switch between the two. A great DAC (and can also serve as a tube linestage) for well under $2000. Very smooth sound with no graininess or digital glare. Seek out the review by Lynn Olson on the Monarchy website.

Add $500 more and you can combine a great dac with a killer transport all rolled into one- Raysonic 168. The balanced tube out is so good I eliminated a $3K preamp

The Kora Hermes at slightly over $1000 used is a great buy IMO.

Much more natural sounding to my ears than the Benchmark.

Based on my experience (which I have not listened to the Benchmark but one or two times) is the Kora Hermes, which I think is a terrific DAC and the MF Trivista, both at used prices right around $1K.

I have a Monarchy NM24 and it sounds great after i retubed it. Not bad stock.....but the circut is clean and with the option of both SS and tube dac and a LS for about $1100 discounted it's hard to say no. BTW I'm going to try some Mundorf supremes to replace the stock Wima coupling caps...it is supposed to be a stunner.