I am also quite delighted with the sound (music playback). I slightly disagree with you and @GreenAndFair though when it comes to basses. To me they sound just right and not particularly emphasized. From my experience and from what I have read in the past, in-earphones actually always run the risk of losing/missing bass if the silicone “seal” in your ear isn’t good enough. In other words: in-ears should usually tend to sound tinny rather than bass-y. Although I’m using the biggest silicone parts with the Fairphone TWS, it still doesn’t feel like I’ve hammered them into my ear channels to the max, and yet the basses are there. 
All in all, I find the sound pleasantly balanced, and I agree with you on how they sound significantly better than Fairphone’s discontinued wired Modular Earphones which suffered from … let me call it droning. Details were getting drained a bit in too much lower register walls.
I have only taken two phone calls with them so far, and this is where they didn’t sound that great. A bit of a radio communication sound that I didn’t have with the same caller when previously using Fairphone’s modular earphones.
Sorry, I am also not an expert, so my terminology might not be up to the highest standards. 
Grateful for your takes @GreenAndFair and @TrueCherry