I got into rFactor a few years ago. It is only for Windows, so I ran it on the Mac via Boot Camp. The physics was less convincing than Geoff Crammond's Grand Prix series, but what attracted me were the add-ons, like the Le Mans 24 circuit with choices of 1972 or 1991 layout and scenery, and cars of all ages and types. However, driving a simulator can not match the sensations of driving a car. Not remotely. It doesn't mean they're not useful to someone learning circuits, as flight simulators are useful to someone learning instruments and navigation. I often have this in mind when reading luke-warm comments from real pilots about X-Plane or FSX. Ignoring the 2D screen and lack of g-forces, which is a handicap for all desktop simulators currently, my greatest criticism of most driving simulators, including rFactor, is the amount of work one has to do to keep it in a straight line. In the end, once the novelty of all the fabulous and beautiful cars and scenery had worn off, my interest waned. Even so, I would certainly recommend it for anyone who enjoys driving simulators, because it is the best of its kind. Guy.