I always take a hand held, battery GPS with me. This will allow us to cope with electrical or vacuum or pitot/static failure reasonably well. It would also help greatly if we ever (heaven forbid) lost both electrics and vacuum.
Hand held GPS are just wonderful for situational awareness when flying IMC, but how would it help if you lost all your gyros? If you lose all your gyros, there is cloud to the deck and all you have is a hand held GPS you have to accept you are likely going to die. If I lost all my gyros in IMC I'd try to get into a spin and hope I could recover if I broke out.
That PCEFIS is neat.