Still not much difference from FSX. Every plane has the same plain text file with flight dynamics description, although they promise that the "rails" are gone, they added the atmosphere modelling over the aircraft (as in XP), so will see....
But XP11(12) can easily update its atmosphere further and better I'm sure. So in this competition we will see how XPlane model will be better again.
Regarding XPlane, of course not, I suppose even more people will use X-Plane, especially Linux (like me) and MAC users.
And most Windows simmers will fly BOTH simulators.
And yes, I think X-Plane has much potential (don't you think the Laminar will not give up?), but someday they both will become the same, identical in terms of flight (the good picture is not a problem - it's a computer power problem)