I'm not familiar with the sound of the Benchmark. But if you are happy with it, I would go with the mini. That is what I did and it was a very nice improvement over the Node 2i. My take on it is this. Since the D2 is only 300.00 more than the U1 mini, you can't be getting a world beater of a DAC. The D2 probably exists for those who want a one box solution.
My vote is for the Mini.
Oz
My vote is for the Mini.
Oz