I'm about 50 hours in now, and the sound is evolving beautifully. It's a really great sounding IEM, and the sound is still improving. The largest change in sound has been occurring in the treble -- it's getting much smoother and more detailed as the hours go on, and it's becoming less sibilant. All I'm doing is listening to them normally (~25-30% volume), and I let them play overnight while I sleep, if I remember. Sibilance is becoming less of an issue, which is definitely a good thing. I've been using the track Vaporous by Elsiane to keep tabs on how the sibilance issue is evolving, and that track is finally becoming enjoyable (the bass texture is awesome and the voice is quickly losing its sibilance).
The iPod Touch really pairs well with these earphones.