CwLondon -
I don't know if you're still looking for info about this, but I was in the same boat as you about 6 months ago.
I first bought the Ety 4S based on Internet reviews and popularity. I HATED them. Least favorite audio purchase I've ever made. I tried every day for 2 weeks straight to like them. Tryed different amps, sources, music. They were uncomfortable, and sounded Oh so bad. Bass was non-existant, thin mids, shrill highs. I tried all sorts of things with ear placment, "getting a seal". Though many disagree with me, I think they are total junk.
I sent them back and bought the Shure 5c. FINALLY, this is what I was looking for. Full midrange, solid bass, highs that don't hurt my ears. Also - much more comfortable to wear than the Etys - You don't need to jam them all the way down your ear canal, just kind of poke them in. I also got the Sensaphonics 2xs on loan to try out. They took the Shures one step higher - a bit more resolution / naturalness of presentation. But for me - they were not worth the price differential. I kept the shures, and have happily been using them ever since.