Hi All -
Just wanted to drop a note saying hello to everyone in this thread.
I'm a new AK120 owner. Just sold my iBasso DX-100 and replaced it with the AK120.
My 2p - I have to agree with the reviews about the DX-100 sound being slightly better than the AK120. However, the AK120 form factor, battery life, double microSDXC card capability, better GUI, charging, indexing and stability just blow away the DX-100.
My greatest frustration with the DX-100 was having to wait 10 minutes every time I turned it on before I could listen to music. To be fair, I had an external microSDXC -> SDXC adapter and was using a 120GB SDXC card. Both the card and memory were full, so it did have a LOT of music to index. However, the AK120 can be set to only index on demand - a great feature. I've got 2 x 64GB cards in it, and my internal 64GB memory is full. Even with 192GB (172GB formatted), it indexes a LOT faster that the DX-100.
I'm using my new toy with Heir Audio 4.Ai and 5.0 cans. It sounds great with both. I had planned to sell my 4.Ais when I got the 5.0s. However, I find that some music is better with the flatter 4.Ais and some with the warmer, more bassy 5.0s. I've done a bunch of side by side tests which, unfortunately, had just made me want to keep both (damn you, Head-Fi, damn you :-).
Overall, I'm a very happy new owner.