I always thought that the E07k was quite good. I never had a chance to really test them out in a quiet environment.
I'm actually quite disappointed with the product actually. Plugged into my Sony Walkman via the FiiO L5 LOD cable the E07k emits considerably more hiss on every IEM that I've tried. Useless as an amp if you ask me.
With that being said, my E07k is up for sale if anyone wants it. Comes with all the original accessories and I can throw in the LOD cables if you want. PM me if you're interested.