It's pretty good - the maths behind it are far more rigourous than MSFS - it uses blade element theory to calculate the dynamics of the aircraft and the visuals are all done in OpenGL, which is the way forward as far a graphics are concerned. The nice thing is that you can design your own planes in Planemaker, customise the terrain (the default is a bit boring) in Worldmaker or you can do what I do and download what other people have done and just play with it. The scenery for Schipol and Holland is particularly good as is the scenery for Rennes - which incidently was my first stop on my solo qualifier cross country!
All in all, a nice little sim - very powerful and looks great. Check out the websites
http://www.x-plane.com
http://www.x-plane.org - this site has many different planes, sceneries, textures, objects and the like to download.
Hope this all helps...
VTOL
_________________________