New E3 owner here. It took me a lot of time to go through the whole thread and I must admit I couldn't stop smiling while reading it. It's incredible how many different opinions were shared here and how almost all of them were true for me. Let me elaborate.
First, when I was trying E3 at my local dealer, I thought they were quite nice, but very plasticky at the same. I didn't quite get it why they get so much praise for their tuning etc. Assuming there may be something wrong with me and thousands of people on the internet cannot be wrong, I took them home for further listening.
At home I felt like they sounded tad better, not as much as plasticky as before, but on the other hand, I was underwhelmed by their extremely soft bass and "flat" presentation - most instruments and vocals were lacking proper weight, they were more like a thin wall of sound instead of a 3D image. I was even more confused. I started tinkering with my set up, switching modes, gains, opamps etc. trying to make them sing. As a result, I think I was getting more out of them, but I was still underwhelmed. While the flat effect was gone, the midrange (especially lower midrange) started to sound veiled to me, I missed some presence there and I cought myself cranking up the volume to get more of that, which in the end resulted in very bright and V-shape type of sound. E3 started to be fatiguing to me, so I continued listening and tinkering. Finally, yesterday, they started to sound like (I assume) they were intended to. It's mind boggling, it's like somebody opened them up, bass is tight and authorative, midrange is nice and full, maybe a tad forward in some tracks, but still very tasteful and very well done. Stage got much bigger and holographic. It's like a completely different headphones to me. Not sure if that's the effect of brain burn-in, the actual burn-in or anything else, but it made all the difference in the world and it took me +-5 days to finally be able to appreciate the headphones.
I guess the conclusion is that if you feel underwhelmed by those (or really any) headphones, give them time, don't go back and forth with other cans, allow yourself to get familiar with them and it's very likely that you'll end up very satisfied with your new buy.