So I got mine. Wow what a UI, both software and hardware are pure perfection! My expectations were not very high after reading about FiiO X5 and iBasso DX90 and their UIs. I have a Sony Xperia S, so I was right at home with the Android interface. The screen is beautiful - and the fact that it's a full Android device I can actually use it at the gym to track my performance, so no need to lug around my phone. It supports MP3gain tags - missing from the competition -, which is a must since I listen mostly in shuffle mode. And you can't beat the form factor and battery life. So much to like!
Volume is ok on my Kef m200 IEMs. At loudest setting it's good for long-term "loud" listening, not too loud, just right. But when I really want to blast, I'd prefer more power, so might end up buying an amp for that. I tried it with my Sennheiser CX300II, and it's damn loud with them, so I suspect there is no EU cap going on, and that the low volume is due to the Kefs. It also warned me the first time before I went to full volume, but I could go a few notches louder, which also suggests there is only a "soft" cap.
Haven't tried with high-res files, yet, currently updating firmware. But I already heard some nuances in my mp3s which I haven't noticed before.
How do I get album artwork to the player? Is there an app that can pull it based on ID3 metadata from the net, or do I have to copy over cover.jpg? If latter is the only option, I might be SOL since I don't copy full albums to the player, and don't use folders. Or maybe there's a naming convention for the image files so they can be matched to individual tracks?
Does an amp improve audio quality with difficult-to-drive IEMs like the m200 even at normal listening volume levels, or is it only for loud listening?