So I spend two days at Axpona this spring pretty much confined to the headphone room. Having not owned headphones for several decades, the wearability without physical fatigue was my concern, along with sound quality of course. I ended up purchasing the sennheiser HD800s. Having owned them for six months now, I am happy with my decision. Very comfortable and I can wear them for a couple hours.
As for the sound- I have done two things to tweak the sound. First, try different ear pads. I purchased a couple of the Dekoni models, each less than $100. Each has an effect on the sound (albeit not dramatic and mostly on the bass). And each fits/feels a bit different. I settled in on the fenestrated sheepskin. So for a couple hundred bucks, a great way to tune in your comfort and sound. I suspect replacing to OEM pads on other brands might also affect the comfort level.
but even more importantly, upgrade your cable. I purchased some from Lavricables (based on recommendations from others on a’gon), balanced, uses silver wire, and they made a dramatic difference in detail, soundstage and sweetness of the mid to treble without making them bright. If you thought the HD800s had too much treble, my experience says these cables smoothed it out. I spent about $800, including a break in service. Highly recommended.