I preferred the sound of the 1350s as well, although I was in the minority (several of us compared them at a headphone meetup). Regarding comfort, I have actually gotten used to the clamping force of the 1350s. It's like a nice comforting hug. While the earpads were certainly softer on the T51s and it was easy to get a good seal, I constantly felt like the headphones were going to fall off my head. The lack of an adjustable split headband also really bothered me.