The 13.4’s are considerably lighter, and have less headband pressure. The flexible mic boom is also nice. I’d say they are more comfortable especially on long legs. There is also a stereo version for a couple bucks more.
Now that I’ve been using a Bose, I don’t think I could use anything else. Absolute most comforable, best sounding headseat available, but pricey.
Oh… here’s a cool headset wizard.