I've had both services simultaneously and noticed two differences:
- Catalog
- Sonic differences
Overall I found more music I like listening to on Tidal. I did notice Quboz had a plethora of versions of some songs (high def if you will, remasters, live, etc.).
I felt there was some harshness impacting high frequencies on some of the music I listened to on Quboz - could have been the specific recordings.
I have Tidal at a discount as part of my Plex subscription so I chose to go with Tidal.
Catalog drove my decision.