New pc laptop vs 2009 Mac Mini

same rips?

Yes. It's the soundstage that changed the most. the imaging is about the same. AIFF and some internet radio. I listen mostly to sfsound radio on itunes, under the classical heading. 

are you using a separate DAC?

Mytek dsd 192, Music Reference rm10 mk2, harbeth p3esr.

By the way, sfsound radio is contemporary electronic and improvised music.

maybe the USB or other output has better galv. isolation, or injects less noise

What's the latest consensus, windows vs osx?

OS-X is really a very nice shell for UNIX.  That can be a big attraction.  It is also getting a new file system, as we speak.

For audio use it doesn't matter really.  If anything delivers the right bits in the right order at the right time you will hear no difference.

A better DAC helps, galvanic isolation helps, and top notch speakers and room treatments are the biggies.

So If you already have the Aida speakers, you are set.  IF not, then get those or the top Maggies, or ...