Forgive the takeoff on a pork commercial but I was sent this link to an interview with X-Plane creator Austin Meyer on Macologist. For those that don't know, X-Plane is the primary competitor to Microsoft Flight Simulator in the civilian flight sim market, although it is a pretty niche product. Even so, competition is a good thing because it spurs innovation and I'm always facsinated by what Austin is working on. He's a very talented developer and X-Plane is a significant accomplishment for which he deserves credit. He's also a very entertaining person to listen to. I've heard him speak at a couple of conferences and found it an unforgettable experience. I thought you might find the article interesting.
 
Austin is forever comparing X-Plane and Flight Simulator and you can read his criticisms in the interview, altough it appears he hasn't really spent much time looking at FS recently, based on his observations. For my part, I haven't spent much time with X-Plane recently either, so I'll make no attempt to rate the two products' merits. I did find one comment very interesting, though. In trying to summarize the differences between the underlying flight modelling he says:
"In Microsoft Flight Simulator, you've gone and told the program how you think your plane should fly, and in X-Plane, you tell the program what shape you are flying, and it tells you how it really flies."
I couldn't have said it better myself! As he states in the interview X-Plane is primarily an engineering tool that appeals to engineers for its ability to generate data. If you don't actually like how the simulation performs that's too bad since that what the data says. With Flight Simulator we're trying to appeal to a broad audience who are looking for a positive entertainment experience. Futhermore most of our users have never and will never pilot a real airplane. So, while we do base our simulation on real-world aerodynamic theory and data, we have the luxury of being able to tailor the experience to better match user expectations. A lot of people get hung up on the ellusive concept of 'realism', whatever you want that to mean, and forget about more humanistic goals of satisfaction, inspiration, accomplishment, and joy. That's why I love working on Flight Simulator--because I actually get to offer that to average people around the world ever time they fire up a copy of our product.
 
I encourage you to make the comparison for yourself. The article includes links to numerous resources on X-Plane, including a trail demo. Enjoy!