I’m not a pilot, but I have spent some time in a full motion sumulator, a B757-200 one.

The principal difference was initially the motion effect as well as the atmosphere, as it feels and looks like an actual flight deck.

The graphics were amazing for their day (1992) and fairly realistic, although I dare say things have since improved. The main difference graphically, was the entire field of vision you got looking out of the flightdeck windows, as opposed to a screen on a PC which only gives you a sideways view when you press a button, and not when you turn your head. Also the graphics were very smooth – no dropped frames or big hourglass icons suddenly appearing!

The only downer was the sound quality. The engines and so on sounded realistic, but I think the speakers were duff because none of the automated voices were clear. For example when I was “landing” the computer told me “don’t think” which made me confused. Apparently the speaker had a lisp, because it should have been “don’t sink”.

Anyway, sorry for the rambling and non-expert reply, but to conclude I would say that current PC sims are useful, but they still don’t compare at the end of the day, due to the limitations of field of vision, graphics, sound, motion and atmosphere. I don’t know enough to comment on flight physics or anything like that.