One small point on using a GPS for heading information. The magnetic compass that's available in some GPS units burns through batteries, but is not necessary if you are moving. As you walk a GPS will give you "course" (vs heading) information.

I use a GPS routinely, but I always take a compass (or two) also. Besides bears, many survival situations start with a simple navigation problem which results in a person wandering around lost or (better) grabbing a tree. Back-ups for critical items is always a good thing.