This is hardly a new subject as the units have been around for quite a while, but two years ago I built a Raspberry Pi 3B and added a HifiBerry DAC+ board to make a Squeezebox player for my basement workbench system.
About a week ago I brought the RPi upstairs and tried it in my main system. I set things up so I could directly A-B the RPi against the Squeezebox Touch which feeds a digital signal to the Bel Canto C5i's DAC -- even got them level matched for volume.
It is amazing just how good the HifiBerry DAC is. Switching back and forth shows the RPi system has the same tonality, depth and clarity as the Bel Canto's DAC. I was very impressed.
Since the RPi, with DAC, case and power supply can be put together for only about $100, give or take a bit, it is an amazing choice for anyone who wants to get into playing their own ripped music or start online streaming without laying out the big bucks. They are up to Raspberry Pi 4 models now, which are a few bucks more than the one I have, but I noticed 3s are still available. They say the 4 really isn't necessary unless you want to get into 4K video.