It's not as pretty in some places when compared to FSX, but it's a solid simulator, and it's the best one out there for civilian helicopter flying and VFR navigation, due to the accuracy of the roads. If you want better default flight dynamics and don't have quite as much to spend on addons I'd go for XP10.

Overall, if you have money to spend and are okay with the occasional crash on longer flights and are willing to get it running well, I'd reccomend FSX, due to the fact that it has A2A, ORBX, and other developers working with it. You still have taxiway signs and whatnot, though. It's moreso a problem of not having buildings. It's also not quite as realistic in the scenery department, though that's being worked on, and a lot of airports are flat with default scenery, though I still have no issue navigating them. There are more than enough to justify buying it, and it's paradise for people who enjoy flying older airliners (FlyJSim is an example) and helicopters (Dreamfoil makes a lot of good helos). The downside to X-Plane is that it's lacking in addons. It doesn't necessarily run better than FSX, but it is capable of fully using your GPU, CPU, and RAM, assuming they're up to it. X-Plane also has the ability to fully utilize a newer PCs hardware. X-Plane's flight model is generally better as a result of this. It calculates what the airflow over the wing is doing in real time, as opposed to FSX which essentially uses a chart to look things up and apply them in order to get fairly realistic behavior. X-Plane 10 is more of a realistic aerodynamics platform. It has a very good flight model for what FSX is capable of. It isn't as good with flight modeling in the default planes, though addon planes can help that. It has more support as far as visual and aircraft addons go (Though XP10 is catching up), and the UI is generally a bit easier for people to understand. For the most part, FSX is a better addon platform.

X-plane vs fsx