Here's a suggestion, why not ditch the list provided in the article and spend your cash on something else.
Buy a phone with a decent DAC and adequate power output.
My LG V30 has a quad DAC, it will handle virtually all codecs, including 32 bit @ 384khz and MQA. It drives my 300ohm HD580s with ease. And it cost me, new, about the same as the cheapest device in your list.
Basically, you don't have to remove all that cash from your pocket to make room for a second device.
How much did Cowon and A&K pay you for this article?
What about the Fiio? Hiby? Shanling? Sony? (m11, m15, m17, r3 pro, r6, q1, m3x, m6, a105, zx500, wm1 a/z)
All of which offer more at lower price points compared to whats suggested here.