I've only spent an hour with the Amiron but I'm very impressed so far. My primary 'phones are the HD650 and HD600 which I switch between, but I agree with the early comments that the Amiron have a superior sound. They have the warmth of the HD6X0, but with more presence in the treble, though without being overbearing like the DT880's treble can sometimes be. Overall, the Amiron seems more balanced across the frequency range than the HD6X0.
Comparing the Amiron to the Elear, the Elear does have a little something the Amiron lacks - a greater dynamic impact or punch, a little more detail, a little more sub-bass - but the Amiron again seems more balanced across the frequency range. I think I will find myself using the Amiron more regularly, saving the Elear for special occasions so to speak.
The build quality is pretty good - definitely superior to the DT880 - but I would expect a little more for the price. But I guess the mostly plastic construction does keep them light & comfortable. BTW, are the ear pads replaceable?
The cable is also pretty good, though too long for me; again, definitely superior to the DT880. I'd recommend buying a 1.4m Beyerdynamic T1.2 cable, which I purchased recently for my Elear and which also fits the Amiron. I can't say that it necessarily sounds better, but the quality and length is much better than the stock cable.