I would notice two big things that would be different: toe piece adjustment and heel retention.
The Salomon toe piece for the 810s (not the Z series) is pretty adjustable. This is good if you have a worn boot sole, as it allows you to lower the binder, while the PX toe is not adjustable. However, I find that I have to retighten my S914s (more or less the same toe, with more metal) after hard crashes or after a lot of use, so it may be worth it for that. The Look toe is one of the safest in the industry, and functions very well.
With my Salomon heels, I am either in or out, there is no in between. However, the heels on the P and PX Looks have probably the best retention of any binder, meaning that when you almost come out, but don't quite, they will pull the ski back onto your foot. This does not happen with the Salomons, and I notice basically no prereleasing with my Rossis (same as the Look binders) while my Salomons have to be cranked to 11 to keep them from prereleasing on hard landers.
Hope this helps.