Hi guys, this is my first post and my first review.
 

I own a useless Fiio X3, its battery died and I have removed it because it was inflated for unknown reasons (I used to charge it with a Samsumg 5.0V 2.0A original charger). Although I was not impressed with the sound, I liked the solid construction and the features it has.
 
Then, I got the Fiio X5, again the solid construction, features etc. had impressed me but in this case the sound impressed me too, at least I felt that I was using a real Hi-fi DAP, I was happy with the X5 (but I decided to sell it).
 

 
Finally I got the DX90 too, I was interested in the iBasso DX90 because I had been reading a lot of good things about iBasso and its products. I have heard about its nice detail and impressive separation and in second place I was looking for a DAP that tempered a little bit the forward sound of my headphones (RS1e).
 
The things I like about the DX90 over the Fiio X5 (Firmware 2.20) are; its touchscreen, size, weight, replaceable battery (compatible with the Samsung Galaxy III), far better SDXC compatibility, and its OS based on Android (right now I have the Lurker0´s 2.2.0 L0 Firmaware, but also exist the Rockbox option).
The UI although not perfect so far is very good, intuitive and usable and I love the physical buttons in the front too. Like with the X5 I never had problems with the file scan or external DAC (Windows 8.1 64 bits).
 

 
The DX90 is very detailed, smooth, very exiting sound and great instrument separation, right now is my favorite DAP and I highly recommend this product.
 
Note: the new 2.2.0 FW has introduced a great SQ improvement and features, Ibasso as always is working on it, great post-release support!
 


(Updated with some pics)
 
Saludos!