So, I picked up an ie600, and my impression is a bit different from
baskingshark .
First of all, I'm no audiophile review expert, so take this with a grain of salt, and this represents my preferences only, along with my middle aged ears which definitely impact what I perceive. (let no one tell you differently!)
I found the ie600 to be excellent, but not quite as good as the euclid. The euclid has more clarity, detail, AND, to my ears, slightly better bass. Both slightly more volume and better controlled. Now don't get me wrong, the ie600 bass is not poor by any measure. I just find the Euclid a bit better.
It's noticeable, but not a world shattering difference. Given that baskingshark claims better audio on the ie600, it makes me wonder if one of us has a ear fitting/seal problem with one of the headsets. (more likely me.)
The ie600 wins hugely on comfort though - I can wear them for much longer durations. I have to take out the Euclid after an hour or so.
If I only had to pick one, it would be the Euclid. I'm going to keep the ie600 though due to the comfort advantage for longer listening sessions.
I'm using an m2 macbook pro for these comparisons, so no fancy AMP here, only the (apparently good) built in amp.