I have a mate in the UK who is an A320 driver and for some reason every X months needs to demonstrate a precision NDB approach? he uses FSX to bone up on this. I have used FSX to hone my intercepting radial skills for VOR's and flying DME Arcs (looking to get my IR ticket someday) Sometimes i even shoot the odd CAT II approach into NZWN, the great5 thing about FSX is you can dial in exactly the weather and VIZ you want so you can have 0 Viz to 500ft pop out of the cloud layer and hopefully the runway should be in front of you. very useful, but should never be used for VFR nav or flight skills there is juts not enough feedback for this and the power bands are usually unrealistic. In FSX i can barrel roll a tommie easily... not to sure the real thing would do it and hold on to the wings.