The clamp of the M-100s is great since the headband can be molded to the shape of your head. Pad-wise though, after ~30 minutes my ears start feeling uncomfortable and after an hour, I have to take them off and rest for 5 minutes or so because they become very painful for me. I have regular sized ears that only protrude slightly, but comfort is still killer for me, which the XL pads should fix. Isolation wise, they are lacking since they are a closed headphones with vent ports. I actually prefer it like this though since I can still hear some things around me while I'm walking around, but this is just a personal preference.
My pads shipped around an hour ago. Ordered on the 15th of September. Hope they get here by next week, but I live in Canada so shipping sucks.