I got two of the four pair of headphones I wanted to audition today.
ATH-A900x - A nice sound with a good, warm, curve to them. My big head takes to the slightly loose feeling fit alright as they don't shimmy around as much as it feels like they should. Overall, a good isolation to them as well, but it feels like it's wanting more power than I have at this moment. (I have a Schiit Asgard 2 on the way to pair with the X3 I got on Massdrop earlier this month)
AKG K701 - No question that these are some of the most detailed speakers I've put over my ears. I'd go so far as to say they're within the realm of my JH13pros, but they're being repaired so I can't do a direct A/B currently. As far as signature goes, they're a little brighter than the ATH with a nice initial bass hit, but there's no resonance (which I like a lot). They're comfortable as well, but maybe not the same kind of comfort I've had in headphones before. They definitely want more power than I have available right now and they're the main reason I decided to get a headphone amp and specifically the one I chose, so that opinion may change in a month or so when I get the amp up and running.
I'll post more once I get my jh13s back from repair, my grado sr225i finished with the cup mods I'm doing and also when I have the HE400s and HE500s as well.
I plan to only keep 3 pair of the 6 I have or will have, so expect the ones I decide I can live without to pop up here for sale at a good price around October - November.