I've got the large bindings but I'm wearing a 10.5 Burton Moto. I love the responsiveness of the bindings. I'm with Oldman, if snow gets under the boots, it is too tight.
I broke the high back and used a rental flow m-9 binding (back foot) and it was way less responsive than the nx2-at. I'm glad I went with the nx2-at.
Only complaint I have is they are tearing up the top of my boot on my back foot from sliding in. I guess that's the payback for a 5 seconds strap in.