Let's put it this way. During my first few hours of flight training, one of the first things the instructor told me was to "put away the sim" (although that was mostly because I was focusing too muchon the instruments rather than the VFR horizon flying that's required at basic PPL training level).
I did as I was told, and have never touched a PC sim ever since, and my flying only continued to improve during my training.
On the one or two occasions these days when I've had an opportunity to spend a few minutes on someone else's PC sim, I've always found them horrendously unrealistic, even ones like Xplane that make (or at least used to make ?) silly claims about how realistic they are.
Short and sweet, there's no comparison to the real thing.
Edit to add : Just re-read and you're mentioning the 6-axis stuff..... yes they are a big step up, but in the end it's just a computer simulation with lots of fancy algorithms and you're just sitting in a box on some hydraulic legs..... so there are limits as to how well you can simulate the realities of aerodynamics, weather etc. But as you suggest, the goals rather different in what the sims are used for, there's certainly no doubting they are a great tool in the training arsenal.
Last edited by mixture; 14th Jun 2011 at 15:05.