The Benchmark is not side stepped by audiophiles. Plenty bought and sold every day by discerning 2-channel enthusiasts, just check out Audiogon.
To some people, the Benchmark is slightly edgy, a little thin sounding, somewhat clinical, which drives dissatisfaction long term and leads them to say that it isn't very musical (whatever that means to you).
For others, it's quite good. And all they will ever want.
Other points:
I doubt the HDR as a preamp is much to write home about.
The headphone outputs on the regular DAC is so harsh that listening through headphones shreds my ears in less than a minute.
The USB implementation is known to be inferior to SPDIF direct.
Despite their claims of being jitter immune, there was considerable improvement when I used the Empirical Audio Off Ramp. Before the Off Ramp, I could not listen in my system for more than 15 minutes without listener fatigue.
Having owned one, I think it's a great value so long as you aren't easily affected by listener fatigue. Even if you are, system synergy may play a bigger part. If you are listening to, for example, a warm, lush Leben then the Benchmark may be just what the doctor ordered.
