While I have grown quite fond of the Neutron player, I've ventured elsewhere in the world of portable high-quality listening.
I've had a FIIO X5 High-Res player now, and have been auditioning it for about a week. I've transferred all my high-res flac files from my PC w/o any down-conversion from standard-res CD/DVD quality to the high-res sources I've purchased from HDTracks (this took literally hours). I've equipped it with 2) SanDisk 128GB MicroSDs so I should be set for space for a while.
The Sound?
The sound is definitely different. I use the word "different" because I don't want to use any unqualified superlatives that I cannot quantify with empirical data, and alas, there is no "empirical" data to be had. A better question to ask would be "do I like the sound?". And with that, I can answer with a resounding "yes, so far". Time will tell.
In the meantime, it looks like my phone can go back to just being a smartphone (Note 2), and my external amps may, and I say "may" be retired and sold.
Steve