I was concerned about this too, but after adding a $10 headband pad I've had zero complaints about the comfort. At first I didn't think I'd like it over longer listening sessions. Reason being that I've got rather big ears and the pad did rub on a pointy part of my mid-ear. The thing is, they're so light and sit lightly over you ears as opposed to clamping, that I've had no issues.
Well, I have had a little bit of pain in the aforementioned spot, but that was at the end of a long day doing a few hours of OT. They had been on my head for at least 10 hours that day. So, pretty great in my book.