This thing is amazing! I barely used my phone at all in the morning and all through the afternoon as I went about my business. I got sucked in for the evening onwards, but baby steps.
... I'll need to download more music, and get a bigger SD card. I've already played and replayed every single one of them I had loaded onto my Echo Mini these past 2 days.
It sounded really good to me. But this is my first wired audio device in a very long time, so I'm not the best judge of that. It is very likely I just didn't like Sony's DSP.
Edit: I do know that the logic board is where they cheaped out to get to that price point, with most of the effort going into the DAC with 2 CS43131 chips. It has both a 3.5mm, and also a 4.4mm balanced headphone jack like most FIIO products out there recently.