The biggest problem I see for FSX is that MS dropped the development of the sim. Like others before it technology advances and leaves those sims behind.
Ok there is a development industry of addons still attached to MSFS but it really needed a complete re write.
Loaded or on slower computers the sim struggled with stutters and freeze ups.
Like previous sims, Pro Pilot, Fly! and flight unlimited (which prob was the most immersive sim) MSFS will become very dated.
X plane which I never had is still in production so has to be the one for the future until something better comes out.
I have been out of the loop on these sims for 4 years so maybe I have it wrong but they were excellent for working out NDB tracking etc at your leisure in the comfort of your home rather than in an expensive aircraft.
Not a lot has changed as before they were best on autopilot for instrument flying but very unrealistic in the flight dynamics arena.
Periferal views were awful looking at a rectangular screen with pop up windows for sub panels.
Maybe the PC isnt the way ahead but for me the best real deal was always Flight unlimited even if the graphics were so dated.
Pace