SW, we seem to be getting into an endless discussion. Let me end this by saying the DAC1 from Benchmark cannot be considered a random design. They were very famous and popular in the professional arena. They were, in fact, considered a de-facto standard there. They did spend a lot of time, money, and energy before they moved into the consumer market.
I have heard the Arcam rDac quite extensively and I do respect it's capabilities. Arcam also took a long time in researching and experimenting, and their product was an instant success. I am writing a detailed review of the rDac along with Asus Xonar STX, and we can discuss some more there.
Though I have a lot of respect for the results of a listening session, personally, a product that has been measured to deliver good results climbs to level 1 in MY acceptance. I also believe that, given a stock DAC chip, there is only so much you can do with the electronic design. I have personal experience with design boards and instructions from companies such as TI, Intel, AMD, etc., when they release new chips. Yes, you can change the op amps, resistors etc. But the cost to value addition ratio in these cases is incremental at best, and it becomes a personal judgement on how much you want to spend.
Let us just leave it as my strong personal belief.
Cheers