I got a 31.5 mondo boot into a L/XL and centered fine on my board. These bindings are very responsive but not restrictive. I don't know if that makes sense, but that's the best way I can describe them. I only rode Burton Missions and Ride Capos before these, so I don't have the basis for comparison or experience that you're looking for. I am also an intermediate rider at best so I'm not qualified to give a proper review. My riding has progressed since I got these though, I don't feel like I'm fighting the board like I was on my Capos.
I mounted them on a medium stiff free ride board and it took me 5 runs to really adjust to them from my Capos to the point that the board felt sketchy. But once used to them, I'm amazed at how much better they are in every way than my other bindings. As long as the durability is there, I don't see myself in another binding for a while and I'm even going to sell my Capos. I really love them.
But I don't do any park, mostly groomers and trees. If you're doing any park, I don't know if these are the right binder for you, would have to let someone like extremo answer that.
Drinking the Kool-Aid:
2013 NS Heritage 166X
2014 Union Factory