So have had the DT990s for a year and sound wise am still quite happy with them.
Comfort wise I'd say they're fine as long as I'm not using them too long.. the pain on the top of my head is a lot less than before but if I wear them too long it still develops eventually.
That's my overall complaint about them, they're comfortable for 3-4 hours but if I'm wearing them during the day while working to listen to music then I wear them in the evening for some games by the end of the day my ears hurt because the ear cups are too shallow I think; they press a bit on my ears. I do have a different set of cooling foam ear cups on order that look a few mm deeper so that may make a difference. Plus still the top of the head pain, I can shift the headband forward and backward to mitigate but still.. downside of not having hair I guess.
But what I really want is something I can wear for as long as I want without issue.. I could do that with the Sennheiser/Epos/Drop/Whatever PC38x's I had.
After some research I ended up ordering a set of ATH-R70x:
I wanted to try these because they don't even HAVE a portion of the headband that goes across the top of the head!
Trying them out a bit can confirm they're super comfortable and a lot lighter than the DT990 Pros. Ear cups feel just a tad deeper which we'll see if it helps with comfort.
Sound wise they're a lot more forward or present, but I'll have to play with the EQ as I think the mids are a bit high.. everything else sounds good so far.
Probably the only real downside so far is the cable plugs into the headset are keyed so that you have to rotate them to lock them in place. Not sure if that's a standard of some kind but if it limits my ability to replace those cables then that would suck. The DT990's have a coiled cable and I'm finding I really like them compared to just a loose cable but not sure if I'd be able to find such a cable for the ATH-R70x.