Benchmark DAC3 or Bryston BDA2 or 3

Nope, I was wrong - sorta.  The BDA2 and 3 both measure very well as does the Benchmark.  Price is the most significant difference I see and how it sounds in your system.

Mahler123 From reviews and Stereophile apparently the Bryston Dac measures superbly, as good as can get according the their testing. 

Apparenltly due to class a output and no op amps the Bryston sounds almost tube like smoothness and slightly less forward than Benchmark which also scores very high Class A+. 

The Bryston plays PCM up to 384khz and 4XDSD. I only have a few files like that but the Benchmark stops at 192 and 1xDSD. Not worth the price to switch to the Bryston but Audirvana can upsample everything to that.

Any thoughts on the benefit of the super-high sample rates above 192khz and DSD beyond 64?

I would agree that the Bryston has a tube like smoothness.  A few months ago there was a review in TAS about  Bryston CD player, which has the same AKM chip as the DAC3, and the reviewers comments about the CDP were a very good description of the sound of the DAC3.
  One reason I bought the Bryston was because it has HDMI inputs.  I have a large Classical SACD collection and I can output the DSD layer of the SACD from my Oppo 105 into the Bryston.  At the time I also had a Mytek Manhatten and the difference between the two was instructive.  The Mytek is like an XRay machine, or perhaps an MRI, in that it reveals an overwhelming amount of detail, but still manages to be musical.  The detail is there with the Bryston, but it is more of a mid Hall perspective instead of front row.  They are both fantastic but I grew to prefer the Bryston, and while I gave up MQA ability when I sold the Mytek , for me the HDMI feature was more important .
  The Benchmark struck as being detailed but hard digital.  Again, I heard in in a suboptimal environment.  If the OP can audition the two DACs in his own system, that’s the best way to decide