Did some brief mention in my review. Basically, more resolution / recording studio-like accuracy to the QP1R. ZX2 is more musical.
ZX2 gets the nod for Android apps and NAS, TIDAL, DEEZER, etc and longer battery life. Touchscreen too.
QP1R has MUCH more amp output so you can use pretty much any headphone without needing an external amp.
Storage goes to QP1R due to two microSD slots and cards add more flexibility versus on-board memory (swaps cards is easy between devices)
Precision in soundscape / channel separation and instrument width precisely defined goes to the QP1R.
Available accessories goes to the ZX2
There's more, yet those are the 'basics'. My reviews of each gives listening notes, etc. As always, it may simply boil down to what you prefer to hear at a given point in time. If you like power hungry headphones the Sony might need an amp whereas the QP1R generally doesn't.
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