Got my E3c's today and listened to them a bit over lunch. I can't really listen to music while I work (too distracting) so I only got about 30 minutes or so with them. I was able to get what felt like a good seal (I could feel the suction, like wearing a pair of ear plugs) with both the clear and grey flex sleeves (medium of both). Isolation was better with the clear, which I expected. I think the clear sounded better, but I didn't wear them long enough to really compare them. Comfort was a bit better with the grey (as opposed to the clear). I haven't tried the foamies yet.
Sounds was pretty good right out of the box. Source was my ipod 4g, unamped (which is how I will be using them almost exclusively). Keeping in mind that I'm coming from the ipod pack-ins, everything seemed more detailed and more clear. There wasn't any appreciable harshness. Bass wasn't booming (I played some bass-heavy Goldie drum-n-bass tracks that make my house shake with my subwoofer at home) but was certainly there and detailed. I suspect this will improve a) as I learn to wear them better; and 2) as they break in.
Speaking of which, I am currently running them playing music from my PC, stuffed in a drawer so as not to disturb me. This strikes me as a pretty easy way to break them in playing material that I will actually be listening to. Is there a distinct advantage to using sine waves and the like, as opposed to playing actual music?
Overall, this noob is pretty happy with his purchase. I am sure that, the more I wear them, the better my experience will become.
BHB