I'm gonna stick my head up outta my hole and weigh in here a bit. I just upgraded from the BH, which I liked a lot for its sound, size and battery life, to the bigger JDS Labs C5 (with less battery life). The C5 is just about the same thickness and width as the E12, but is more than a bit shorter in length. It also costs about $80 more than the E12, and $100 more than the BH. It is considerably more powerful than the BH, and I have really been enjoying that power as it relates to the sound I'm getting from my Colorfly C3 and TF10s. And I use it (them) to listen to music (nearly) exclusively while walking. I've never used the E12, so can't say how it would sound with the 10s. And I'm not being pro or con re the current discussion. I just wanted to say that, for me, moving up in power and size, and down in battery life, from the BH has made me happy. And I really liked the BH. I used mine daily for a year, very happily. The BH is a lovely little amp. I still have it and haven't decided whether to keep it or sell it.
Going back in my hole now, gonna try to avoid the shrapnel.