Didn't spot any cosmetic damage

Yeah, it turned out to be mostly material transference to the screen. It appears there are gouges that I can't entirely get out, but I think the coaxial port is also toast. All in all, I'm not complaining considering its a great device.

I don't think its price is high at all, the audio quality is almost on par with Fiio X5ii....and Fiio X5ii is more expensive than AP100...

I did some more research, read up a little bit more, and have come to agree with you @Ted Presley. I've updated my review to reflect that.

You are welcome, I am really looking for an upgrade portable DAP in replacement for AP100 which is quite hard, as the price is way too low for AP100 for such quality sound... My Audio Technica CKR9 is quite bright, and AP100 is alo bright causing trouble while listening for a while (although AP100 works very as a source for my audio system at home).
 
I am consider old DX90 which has a warmer sound.