Received the AK100 today... updated to latest firmware made available on 12/10 and transfered various high rez and CD-quality flacs... after 20 minutes of initial testing, everything plays smoothly and sounds really good with my FTG334s.
Updating the firmware and transferring files was super easy. It was so nice to be able to transfer Flac files without having to convert or compress.
Will try and post pics tomorrow, but I absolutely love the form factor. It appears that I can fit both (i) the AK100 in its soft pouch; and (ii) the FTG 334s in its pouch, into the small pelican case that came with the 334s. This is an unexpected surprise and a huge plus for me and as its the perfect travel setup for the plane.
One of the best parts so far is that I am not hearing any background hiss, which I found very annoying with most of the other setups I've tried.
To be clear, I have not tried the DX100 which seems to be very popular, and I imagine sounds great as well. For me, the size of the AK100 is just perfect. I did not listen to it before updating firmware, so I can't comment on what it sounded like right out of the box. Not sure if the sound gets better after a burn-in period, but it sounds great to me out of the box with the latest firmware.
Anyways, I'm stoked that I pulled the trigger on this and am very satisfied with the initial performance.