Finally got my M6 a while ago, and I'm loving every minute from it. Immediately updated the firmware to the latest one via OTA. Definitely the most affordable Android-based, WiFi-capable DAP you could buy right now. Contrary to what a few others have said in this thread, this DAP actually has great sounding bass, and its bass sounds great even on neutral-sounding IEMs like the much-hyped-right-now Final E1000, and sounds even better on KZ IEMs (in which most of their models has a V-shaped sound signature).
Just noticed something odd when browsing music using Folder view. It seems like the folders' ordering is chronological, not alphabetical, in which I find weird for a player of this caliber. Maybe it has something to do with my microSD card, which is formatted in FAT32.
EDIT: Just Google'd around, and it looks like FAT32 is the culprit. The solution is to use any program that sorts out FAT32 directories. Would try an exFAT-formatted microSD one later.