Hey, I've been debating if I should get Spotify Premium for the sound quality increase from 160kbps to 320kbps Ogg Vorbis on desktop. Please note that the only deciding factor for me is the sound quality in whether or not I'll get premium
I've done some ABX testing(on my hd 600s) with some tracks ...
Warning, subjective comments follow:
The quality difference is huge, but personally I wouldn't trust the HD600s too much on making this difference too obvious. I bought both the HD660s and then the HD600 just to compare them, the HD660s are way more detailed but obviously it depends on the music you are listening to as well and the DAC/Amp you are using.
After listening to your test tracks I would say, the HD600 are fine overall for this type of music and/or the music I used to listen in the past mostly (i.e. Gabba, Speedcore, JCore, EDM etc.) 160Kbps vs 320Kbps do not make that huge of a difference.
Nowadays I have expanded my taste to include more Jazz, Classic, Country, everything...so quality is a bit more important for me and I wouldn't be satisfied with 160Kbps or below.