Alex, I've tried the MacBook Pro in my system and the Mini sounds better
This is not very encouraging. :-(
Now, the last thing I need is some junky Toshiba laptop running Windows making me feel insecure about my sleek, Apple-based audio setup.
Well, compared to MacMini, the "junky" Toshiba laptop comes with a lot better hardware configuration. Apparently, being one of the semiconductor manufacturing leaders, Toshiba has done a very good job designing their laptop motherboards. And don't forget that the best sounding audio equipment uses Toshiba devices (JFETs, MOSFETs, BJTs, etc.).
In all seriousness, I wonder whether there's some kind of issue with the Mini and the Hiface.
The MacMini is nothing else but Intel based laptop, so I dont see any compatibility issues with hiFace or any other USB audio device.
I think my Mini paired with a USB DAC sounds pretty good.
Sure, I agree, it does sound pretty good. It is always like this with audio; you are very happy with something until you hear something better. :-)
Best,
Alex Peychev