My advice? Don't get lost, stay found. How many survival situations have we seen that started out fine and went south fast after the subject got lost. The government has spent $billion$ putting the GPS system into orbit; get an inexpensive GPS and learn how to use that system to find yourself on a real map. Navigate with map and compass.
Non-mapping GPS units work well to determine exactly where you are relative to waypoints or landmarks you program in before you start hiking and during the hike. Otherwise all it gives you is a geo reference (lat-long or UTM) that you need to take to a real map.
Mapping GPS units have the advantage of the map included with the precise position. But you are limited to the info which is in the database. Newer units with memory cards can contain a lot of data but you still need to get in there before you start walking so you aren't surprised to find it lacking when crunch time comes.
The GPS units with electronic compass I've used did a good job at finding true north and were self calibrating. It might be a good idea to have a real compass to compare it to so that if it does screw up you'll know. Otherwise bring lots of extra batteries because the GPS compass works on battery power and it uses as much or more than the GPS receiver. I never use the electronic compass in my GPS, too much battery drain.
I prefer non-mapping GPS units because they're cheaper and universal in that I don't need to worry about which database/memory card is in the unit. A real map and mag compass are the primary nav tools with a small & lightweight GPS (
Garmin Geko 301). It's a nice unit in that it's small enough that you can throw it in your pocket and forget about it. If you want, preload visual reference points (mountain peaks and points you expect to pass by) as waypoints so it puts a cheap map on the display.
Get a good fix at your trail-head (& wherever you park your car) and add those as waypoints, waypoints are free. Then turn it off until you need to check/verify your position. Turn it on, check its position against your map's UTM grid and then turn it off. Batteries last a long time in this mode. Some folks like to run their GPS continually so they can see the little bread crumb trail on the display; IMO that's what the map is for. Maps and mag compass don't use batteries.