E3s showed up yesterday! I'm impressed with how well they sound. I keep forgetting that they're planars. In that same vein, I also keep forgetting they're closed back. The combination of isolation and open sound is wild!
I've been wearing them most of yesterday and today, and the comfort is top notch. I was a little concerned that the ears might get too warm, but while they're warmer than my other headphones they don't progress into discomfort, or even annoyance. At the moment I'm using them with a xDuoo TA-22, and it has no problem driving them, even at low gain.
I was on the fence about picking these up, and am very happy that I took the plunge!