I’ve been using FSX since 2009 and never bothered to try anything else because I’ve never had a powerful enough system. I recently upgraded, and figured I would do the same for the flight sim. After making the decision on XP11 based on the reviews left by former FSX vets - I can truly say this is an excellent product. The flight model on approach and landing is simply exhilarating. Purchased directly as opposed to Steam so the developers get more of the cut for their great work on this.
FYI - do pay close attention to the hardware requirements. You can get the free demo to test out how it will run!