I'll first give AnakChan's first impression of the player. He told me he didn't see much difference between the DX100 and the AK100, but that the DX100 has a more 3D like presentation.
As far as I'm concerned, when I tried it yesterday, I wasn't really impressed with what I've heard. Some things are done well, but some others are lacking. With my T15, the bass and mid were not very clean and bass was slightly emphasized. And I couldn't shake a funny feeling of "fuzzy sound". I tried the DX100 later on, and it sounded clearer to me.
I tried a few different songs, especially Spanish Harlem and Hotel California from Hell freezes over. In particular, Rebecca Pidgeon's voice wasn't as clear as it should be. I had the feeling the edges were not clearly defined, and that's just doesn' sit right with me. Hotel California was not bad, bass impact was there, even if slightly emphasized, but instrument separation might have been better (I'll reconfirm this point today if possible).
On the good part for the AK100, I don't think there's any roll-off, and details are there. Build is solid and the UI is responsive. Only thing I have doubts about is the battery life.
As to the RMAA results on ebay (assuming they can be trusted of course), taking in account that RMAA is not always the best tool around, and that the 16 ohms load is probably a resistor (better than nothing though), the numbers are nothing out of the ordinary. Crosstalk is average at best, which could explain for AnakChan's impressions. Comparing that with the 300 ohms load, the results are clearly worse, which just shows that this DAP isn't well suited for IEMs.
My personal conclusion : I'll stay with my T51 and Pico Slim for now.
EDIT : Please keep in mind that this a comparison at a trade show, without volume matching, most likely at a higher volume than what I listen usually, and standing in front of a table.
lol, load measurements on iriver site. lol