trust me delivering a bug free dac is quite easy compared delivering a bug free operating system such as Windows which has to play nice with millions of hardware and software components. I did not start this comparison myself however I think it is time we end this since they are completely different animals.
The problem with this discussion is that I don't believe any of us have designed a DAC/pre-amp/headphone amp similar to the M-DAC or a Benchmark or anything similar.
DIY need not weigh in either, DIY types don't sell and warranty several thousand pieces.
I can't really comment either, I'm a power engineering, and once upon a time I was an Analog Signal Processing hardware designer, in other words, what do I know about M-DAC's operating software?
I think Microsoft may have a slighter bigger design staff than Audiolab!