FiiO M21

22 May, 2026

Pros:

Nothing significant enough to warrant being added here. If anything, I at least appreciate that it's helped me break free from my mobile and computer when it comes to listening to music, but that's the whole purpose of a DAP (and ultimately part of a bigger discussion point around single-purpose/dedicated devices).

Neutral:

Android doesn't run as smoothly as I'd like and navigation is a bit clunky, e.g. parts of the UI slowly "pop in" as you transition from one screen to another. It could just be hardware holding back the OS (understandable for this being a repurposed low/mid-tier "mobile phone").
Additionally, the out-of-the-box experience doesn't really scream (forgive the qualifier) dumb, which is what I was mostly hoping for (that's on me for not having researched enough). Perhaps Sony or Astell and Kern do things better or maybe it's just an unavoidable aspect with anything that runs Android.
This last point is more on me but I really can't attest to the audio quality in spite of having a decent enough headphones and IEMs. Additionally, none of them have balanced inputs but I don't know if that would make a difference to me.

Cons:

macOS connectivity is non-existent, e.g. if you want to access the SD card directly through the device. Fortunately Super* Review has a more future-proof approach using DriveSync[$] (aka Austosync) rather than manually syncing your library anyway.
As of time of posting, you cannot assign the multifunction button to rotate the screen (and swap the playback button order too). This can be solved using a macro (e.g. via MacroDroid[$]), although it isn't the most elegant of solutions.
The ability to tailor and streamline the overall experience to your liking comes at a cost, literally, as evidenced by the above.