It has some minor irritations, but, overall, it feels like its been dogfooded.

I tried one of the cheapie $20-$30 ones from Amazon and it was clear they just threw the software together.

If UI is your thing, there's an opensource jukebox with an apparently impeccable UI, but you have to get a compatible player and that means buying used because by the time they make firmware for a player, its no longer in production. It also doesn't support Bluetooth, which I thought I absolutely needed when I was getting started, but now I've got more wires in my life.