FSX is good for a different type of flying. What FSX lacks is proper FMs in some regimes of the flight envelope and because it covers the entire planet, concessions had to be made in regards to ground detail. Don't forget it's a 2006 title that had to run on hardware of that time and even today, there are still PCs that struggle. There are countless options to edit in the configuration files, but only recently have people been able to decipher most of them and that's usually through trial and error or even direct but unofficial feedback from the FSX devs, as officialy MS has abandoned it.
That being said and despite its shortcomings, the only reason i don't have FSX is because it's too dependant on 3rd party applications and that makes it a very expensive hobby. One person can be flying 2-3 other simulators with the associated peripherals for the same amount of money needed to bring FSX up to speed. Seriously, some of the payware planes are so advanced that not only they have FMs that correct the stock FSX FM glitches, but also if you happen to fly one of them you'll never want to fly one of the stock MS planes again.
I regularly fly it on a friend's PC when visiting him. We don't do airline long distance flights as it's mostly about programming and monitoring the automatic navigation systems and for a prop-head like me, that's not enough hands-on flying...people who fly Black Shark or Falcon4 would like the complex electronics though. What we do that's great fun, is getting down and dirty in smaller, slow planes or twin engined executive prop planes, bush flying around my hometown in small GA aircraft equipped with amphibious floats, landing in rivers or mountains in bad weather, etc, especially if you have a buddy with you to play "virtual copilot" and set some guidelines for an ad-hoc mission to follow. For example, you can set bad weather and start off in a ski-equiped plane with the aim of landing in a slopped mountain ridge just before night fall, pretending you are a rescue pilot looking for stranded climbers. This was a totally new aspect of flight simming for me, as up to that point all i ever did was combat sims. However, having the ability to simulate events that are much closer and much more likely to occur to out real lives than being a WW2 fighter pilot, is something i found refreshing and quite fun.
One time we made a 10 hour flight in a Catalina in the span of three afternoons, starting from Bahamas and navigating VOR to VOR over Cuba, Haiti, Dominican Republic all the way to St. Maarten while exhancing places behind the controls. One person would fly while the other was taking care of snacks, cigarettes and beer supplies