Just saw this post, an avid fs9 user for years I deced to go with X-Plane due to a recent computer virus....feed up with windows vulerabilities
Switched to Ubuntu Linux
X-Plane is a great sim but lacking even to fs9...mostly because of the limited add-ons available & a much smaller design team then microsoft
Some of the highlights in my opinion are:
Great default terrain mesh and textures....
Silky smooth FPS....
Great flight dynamics....
But a few things really need improvment:
No AI aircraft
The weather engine needs work
By default none of the airports have buildings
ATC needs major work
No default flight planner....a good payware product called goodway is available
But overall its a great sim, although not a direct replacement for the MSFS series