I've had my E1 for a couple of weeks now too.
Overall I love it, it exactly improved the SQ as the reviews suggested on my iTouch 3G (bass back to where it should be, mids & trebles more defined & everything less fizzy).
When I got mine, the buttons didn't work right - eg. the volume up button would start/stop playback, or skip tracks. After pressing all the buttons hard though it suddenly worked as it should (guess there was a minor manufacturing issue making them interact until broken in).
At first it was annoying to hit buttons every time you clip it on something, but I've now developed a technique of holding it at the sides during clipping which mostly works without triggering anything.
One issue though, the play button isn't raised enough, or tactily (is that a word?) noticable enough to find it blind with your fingers, and I'm often changing volume instead of pausing/unpausing. I hope they can address this with a slight design change.
I also would like a mic socket (stereo if possible), especially for field recording possibilites, but also voice control, voice notes etc. I also wouldn't mind a slightly bigger remote if the connector could be made significantly smaller (I believe the amp electronics are at the connector) - it makes the whole contraption a little bulky in my pocket.
But on the whole, I got my remote, and most importantly, the SQ to make me love my music again - I always loved it on my iRiver H140, which is probably still slightly better SQ-wise - but I'm happy enough to defect
.