Things I love about the M1:
1. Form factor/size.
2. Volume control/navigation wheel.
3. USB-C charging and digital out.
4. Great quality screen.
5. Tons of features, i.e., HiBy link, replay gain, perfect gapless playback, USB-DAC functionality, etc, etc. Good job Shanling!
Things I might improve/add in FW version 4.0 if I were really picky:
1. Despite my earlier optimism about my Samsung 256 Gb EVO cards, I still have the occasional boot-up glitch. With my SanDisk 200 Gb cards, my poor M1 would go into an endless boot-loop and would be stuck forever unless I removed the SDcard during boot-up. With my Samsung 256 Gb EVO cards, sometimes it boots up straight away, other times it seems to reboot once or twice, but it always eventually gets there. (But as a result, my M1 takes an unknown amount of time to boot up.) None of my other DAPs have a problem with any of these cards.
2. My FiiO X1ii can be controlled via an Android headset remote (play/pause/forward/backward wind, volume up/down, etc.). I thought that the M1, being Android based, might operate the same way, but it doesn't recognize any of my Android headset remotes. Shanling folks - this would be a nice feature to have...?!