Find some technical specs further above.
Soundwise, I have to say that after a couple of weeks, they’re not really my taste. Bear in mind my only comparison is a very simple Sony set of earphones (Sony MDR-EX15AP) and compared to those, the impression is clearly that the Fairphone earphones provide much stronger bass/lows which might be partly due to the much better physical seal their build ensures. In contrast, I miss some trebles (I am still wondering if the Sony’s imperfect seal just gives me a wrong impression of clearer trebles or if the trebles are really more pronounced on the Sony). My favourite song just won’t excite me that much with the Fairphone earphones. 
There is no distortion or the like though. I saw 1-2 other users praising the basses.
Despite my initial skepticism when I was reading the decibel specs on the box, the volume level is pretty decent (significantly louder than my Sony’s).
I had to get accustomed to the different way to wear these earphones (see the latest blog entry for a helpful photo). But in contrast to the ambiguous sound experience, this is something I grew somewhat accustomed to, although obviously, it is still a bigger hassle to put the Fairphone earphones on and take them off.
Very good: The cable isn’t just replaceable, it’s also more solid than on my Sony which makes for much smaller issues with entanglement. This cable hardly entangles at all from my experience (note: I do store them hanging vertically down their whole length from a shelf at home).
For more practical observations, see the link.
P.S.: Johan, allow me to – just once – recommend these folks in your town 