Got it from AliExpress a few days ago, want to share my initial thoughts, I never tried a Fiio product or DAP from the last decade.

• a very cute unit, maybe a bit bigger than I was expecting.
• Sounds great to me.
• The dial / buttons are serviceable for playback, with all key functions having their own control; volume up/down, next/previous track, and play / pause. In menus pause is 'enter' while holding pause for a few seconds is 'back', which is a bit fiddley.
• While most of the options are set and forget, stuff like shuffle and repeat are a bit of a pain to get to.
• The library browser lists artist and album names correctly, but track names are replaced with the plain filename for some stupid reason. Apparently this was the same on the echo mini, there is a python script to fix up the filenames. Makes it less easy and fun to swap new music though.
• The volume knob has a lot of wobble since the top ring is a bit too small. Makes it feel not as great as it could, sometimes scraping the housing. Unscrewing the top let's you remove the ring, maybe some tape could fill the gap and make it turn better?
• Battery life is an actual joke. After one hour it was noticeably warm and showing half depleted. The original iPod shuffle lasted 12 hours, the Sony B183 lasted 20. My guess is that Fiio are doing something absolutely wrong on the CPU/software side. The DAC/amplifier (Cirrus CS43131 claims 6.25-40.2mW power consumption, while the RKnanoD claims 12mA @ 3.3V for music playback. Just those two should give ~16 hours on the 360mA battery, minus losses from the voltage regulator and screen.
• Comes in Chinese but has a lot of language options. In case you need help; Settings menu -> forth option down -> select language.
• Didn't seem to successfully format the SD first go, needs to be MBR and FAT32, doesn't work with exFAT.
• didn't get a chance to test the gapless playback, it apparently doesn't have it.
• Don't take it apart! The bottom comes off easy, but the top end with the dial has glue along with the screw securing it. The OLED screen has a ribbon cable connecting it to the board that is not long enough to reach outside of the case. I don't know how they assemble these, but it is a massive pain. I ended up breaking the display ribbon cable and now it doesn't work at all 😭