The test was done in a dedicated listening room that has been well treated for room acoustics. The system is a system we are both very familiar with, the listen levels where matched, and we choose the same listening material, started at the exact same time.
We switched back and forth between the two inputs via the Sim Audio preamp. The preamps display was blocked so that the person taking the test could not see which input was in use.
The end result was that we could not tell which source was playing even though we could recognize slight details between the two. Neither was better, neither was worse than the other. The deciding factor was the user interface of the Mac setup was better, plus the ability to access the entire music collection without leaving the listening position sealed the deal.
Like I said up above, cost is no issue. He can have any source player in the world and he has chosen a hard drive based source.