Hi,
as no-one else has responded, and you have provided shedloads of help on these forums..here is my twopennyworth...
the other consideration is ease of use...and that for me has been the deciding factor
I have all of the devices you mentioned (and a couple of others I will gloss over!)....
In terms of sound the FiiO's are very very good but as I enter my twilight years (
) this is off-set by the font which is quite quite small and therefore quite fiddly(as is the interface)..battery life is not what it could be..I have the fiio3..fiddly buttons..the new onehas the scroll wheel..not sure how that goes
the newer Sony's (not the stupid priced ones but the NWA 17 or similar are very good, relatively simple to use and the blue tooth connects painlessly..battery life is very good..60 hours they claim...never got that far as I connect to pc to move music and this charges at the same time (there is the typical issue with Sony and that is that you need a Sony cable..)
Interestingly, I currently using an old (as being defined as 1 year!) android phone (Moto style) ..heaps of memory (currently 128Gb, but supports 256), touch screen..and allows other media (radio and podcasts)..sound quality (with reasonable in-ear) is very good (although as previously noted..the approach of twilight means that maybe my fine tuned hearing is going off!)
the best sounding device ever was a Cowon S9 ..brilliant, bright, full eq, great battery life, fitted in your pocket..but small memory (32Gb) and discontinued
Anyway hope this helps
Cheers