Here's my issue. I will have a Rx MK2 here in a few months and am looking to get into the full size headphones.
Right now the three I'm really looking into are the HE-400, He-500 and the HD650. I currently am running a Westone 2 and E11 and absolutely love the sound, just wish there was a tad more low end involved.
I have read a lot of the threads stating that to really make the HD650 sound good you need a very nice setup. It's honestly got me worried about pairing them up with the Rx Mk2. Is that amp going to shine better with the Hifiman's or the HD650.
Comfort is a large factor for me. I don't care how good they sound if I can only listen to them for 45min before they become annoying.
I'll do my best to answer any and all of your questions.