I thought I'd throw in my 2c on the iBasso.
I've been travelling with an iPod, Galaxy Note 2, and then 3 with the Fiio E07k, and I really wanted a better standalone DAC. I had toyed around with my mate's Cowon and the Fiio X3 - but hands down the DX50 beats it. Bought it, and have had it since Christmas - and I could not have been any happier with it.
I use the DX50 mainly for when i commute (45 minutes each way), and when I travel (fiancee lives 4 hours flight away). Mine's the 13th batch apparently.
It's been paired up with my DT990 pro, Bose QC15, ATHM50, and my westone UM3.
The winning combo is still the DX50 and UM3. Great soundstage, warm, and that clarity! It does an okay job with the DT990, but doesn't do it for commuting. With plane rides, or even working at the cafe, the QC15 and the DX50 is just simply amazing.
I almost bought the X3 second hand off my friend, but I'm glad that I got the DX50 instead.
There are some 'buggy' issues - like audio file name.... folder structures, and even the delay you get from pushing the buttons to get it to go 'next song'. Still, it's an awesome piece of hardware, and I'm glad that my FLAC files are getting played the way they should be.
I'm waiting on a set of CIEM to come... and that may just complete my travel rig!