I've had a vacuum pump go on me whilst in cloud approaching the Channel Islands in a Cherokee. Had to descend through cloud on the (electric) turn and slip / compass. I've also had a NAV box pack up on me just as I was trying to intercept the localiser on an IFR flight into Geneva.
My personal GPS usually seems to loose signal on the South Coast between Selsey Bill and the Isle of Wight.
Rather than see some kind of almost tribal argument develop between those who like to use GPS and those who prefer to use traditional radio navigation aids, I think that there is a pretty strong argument for having (and knowing how to use) both
Oh and I would definitely agree with IO540 . . .
- most Narco stuff is crap