I agree with all the sentiments expressed above, but I do think the performance of all the airliners that come default with FSX are fudged a little bit to make for a slightly less realistic but more fun user experience.
Either way, FSX is a useful training tool.
FAA Certified Flight Instructor, Commercial Pilot and Airframe/Poweplant mechanic CFI/CFII/MEII/CMEL/A&P
American Corporate Pilot and instructor of new hires for Shanghai Airlines
AMD X6 1090T black edition CPU, liquid cooled
NVIDIA GTX 480 1.5Gb GPU
8G DDR3-1600 RAM
3TB storage, plain hard drives