I won't be using a GPS mainly because I can't afford one.
But If I could,I would use the most basic one,just to give a grid ref,and then back to map compass and eyes.(Don't forget the magnetic variation. Do GPS compansate for this?)
Been quite a bit on this, but as Oldun says it's not easy to locate! Yes, a gps can be set to either give you a magnetic or true bearing. compass variation can be quite high in some locations - some of the spots I go to, the difference is over 20 degrees, so if using a gps in conjunction with your compass then it is critical to know what setting your gps is on.
IMO map & compass skill is the ace in the pack, but a gps is invaluable in situations of 'whiteout' or becoming disorientated in featureless or restricted vision terrain.
If the co-ordinates of your base camp are entered before leaving (a simple question of just pushing a button and giving the base a name) then in the event of a 'whiteout' scenario you can immediately get your gps to give you a compass bearing to follow back to your destination. Similarly, if you get the coordinates of your destination from your map and enter them before leaving, then you'll have the option of continuing on.
I remember it being drilled into us that because it relies on electricity, 'radar is an
aid to navigation' and not a substitute for it. Although I often carry a gps and find it offers good peace of mind, I think of it in the same way!