Short answer, Airfoil wins hands down for detail and breadth of sound. Running a headless mac mini in a rack and all wired ethernet, I’m using an iMac to access Roon and playback to my iMac through a DragonFly DAC. I can’t believe how much richer Airfoil sounds.
Of course it’s no comparison to the Definitive 8080’s and Yamaha Aventage 3040 in Pure Direct mode -when I can go and chill out - but for listening and working, Airfoil crushing Airplay.
Too bad because Roon Remote is cool, but AirPlay isn’t.