Wanted to report back some issues and annoyances I've encountered after a week of use:
Mandatory library re-scan after a reboot: This basically renders the M unusable for the first few minutes after a cold boot.
Delayed album thumbnail display: Seems like the thumbnails are generated (slowly) on-the-fly the first time you scroll to that part of the view (I believe the generated thumbnails are then cached until you do a reboot). Not helpful when only the first 10 characters of the album name is shown, and you get a screen full of indistinguishable "XXX: ....". Might not be a problem though if you don't have much classical music.
Poor battery life: 4.5 hours of 16/44.1; 3.5 hours of DSD64 playback (with the screen off 99.9% of the time)
Folder Play: 'nuff said
Sluggish UI in general
Battery leak:15-20% of battery is gone 8-10 hours after a full recharge (obviously the device is off in between)
Sometimes a track would appear twice in the library. A full library refresh fixes the issue.
The first second of a track gets cut off. Happens to the first track of an album being played, just like the X5 with F/W 2.0, HM901, DX90 etc..
No display brightness adjustment
Edited by pekingduck - 7/6/14 at 2:09am