I recently switched from traditional bindings to the Flow M9's. For starters, they're a lot more comfortable because they distribute pressure from the strap across the top of your feet. Once you tune them in, they are A LOT easier to get in and out of. And they are very responsive on the mountain... much better feel than the ratchet bindings I've owned.
However, the M9's are a bit more narrow than any other bindings. I wear a 10.5 boot and usually go with Large size bindings. But when I step-in and make the strap adjustments...I had trouble closing the highbacks...because my boots were a little too wide. I switched out my boots and now the binding fits perfectly.
Also, be patient when trying to adjust them on your first day riding. It took me a couple of runs to figure out that I didn't have to tighten the stap all the way down to get a proper fit.