I always failed to see how people can experience clamping issues with this headphone. Maybe my head is just small, but I think the comfort of these things is just majestic.
Only bad thing is that they get kinda uncomfortable when I lean over to read a book/piece of paper on my desk. As a result I have gotten used to turning on the speakers whenever I want to read a book.
Why would leaning over get uncomfortable with them? It's not like they have the tremendous forward weight shift of planars.
The comfort is excellent on them. It's easy to think of them as clamping if all you've compared against is cheaper headphones. But it does depend on head structure and which of your squishy bits it happens to press on. That goes for any headphone. K702's a stranger one. It's brutally uncomfortable, even painful at first, but after 20 minutes melts into extreme comfort. The big thing with the 650 is to keep the bottom away from the jaw bone. That means putting the headband a little forward, but after dealing with HE-400 I adapted to that easily enough.