So I got extremely lucky and had my Elegia delivered to me today. I had a good amount of time of time with them listening to a variety of music (everything from classical to pop to funk to FLAC video game soundtracks). I also tried them in a few games as well.
First things first. ShiZo is correct, there is indeed minimal leakage. At normal listening volume you can barely hear them 1 ft away. That said, the Aeon Flow Closed have slightly less leakage than the Elegia's.
I'm sure this has been said before but the included cable is short and tangles easily. Short as in your DAC/AMP better be right on your desk or it won't reach.
The Elegia are very easy to drive. If I set the volume to 25% on my JDS Labs Element (low gain), that's enough for optimal listening. The Aeon Flow Closed require somewhere around 40%, just for comparison.
Comfort wise the Elegia are surprisingly good. Not too much clamping force and didn't feel too heavy. The Aeon Flow Closed feels like a light fluffy pillow though. Hard to beat that level of comfort.
Sound isolation (not to be mistake for leakage) for either the Elegia or Aeon Flow Closed are about the same. They don't provide a ton of isolation. Mostly mid frequencies, voices and the like.
The bass was fantastic. A lot of people say the Elegia are base light but to me it seems like they have the perfect amount. The quality of which was exceptional as well. Compared to the Aeon Flow Closed, they provide a bit more oomph exactly where it's needed over the Aeon Flow Closed without making other parts of the song over-done when they shouldn't be. Both have tight controlled base with excellent extension into the lower frequencies but the Elegia gets the win here.
Mids are a sticking point for the Elegia. There were some songs that sound significantly different and not always in a good way. I found multiple songs were the mids took over the presentation of the song and drowned out other instruments or sounds. They were still there but you really had to listen to hear them. In my opinion the Aeon Flow Closed provided a clearer, neutral presentation. I should state that both overall had excellent detail.
Treble wise, the Elegia sounded good, except it lacked any punch. I consider the Aeon Flow closed to not have amazing sparkle but the Elegia have even less punch then that. I vastly preferred the ATH-A2000Z over either of these in this category (that's about the only thing those cans did exceptional though).
For Imaging I felt the Elegia had some idiosyncrasies. If a sound was moving from one channel to the other, for me it was hard to locate it's precise location when in the center. Still excellent overall but not as good as the Aeon Flow Closed.
Last is soundstage. I felt the Elegia had a wider soundstage then the Aeon Flow Closed. Not by much but perceptible. I also felt that sounds coming from the sides and behind were slightly easier to place in games. This benefit didn't really manifest in the music I tested. I'd give the slight edge to the Elegia in this category.
If you were to ask me which I'd prefer, it'd be the Aeon Flow Closed. That said you really can't go wrong with either option.