I’ve never heard a Mac Mini, even when heavily modded, sound good. Playing an Oppo (only heard once) and Ayre QB-9 (which I usually love the sound of) in each case the sound was brutally hard on the top end, no idea why. Currently using Logitech Squeezebox until something else comes along better and under $2k.
There are some new old stock Squeezebox players on Audiogon for around $500 right now. I am tempted to pick one up as a spare, for when the Zombie apocalypse happens.
Best,
Erik