I am just a brand new NPPL rookie. Our training school makes little mention of GPS except "Then you will go & get one & forget all this DR stuff".
Therefore I am at the stage of thinking they may make life a lot less stressful, but, what if? computers being what they are.
I also believe that DR was "designed" in the days when, like James Stewart did, Spirit of St Louis, hang out the window "Which way's Oireland?" So perhaps we do need something more in keeping with this century, But, only after we know the real thing, the batteries last a long time anyway.
So total abstention from GPS till after the QXC/GST, then the offer if required of further training by someone who knows how to use them, not just buy it & read the book.
Many moons ago I was at a nav training evening. The instructor (ex Spit jockey) said "We will plan a route from London to Truro, so what is the track? Being a twit I said "About westish" The guy sitting next to me said in a pompous tone "No no we have to be considerably more accurate than that" fiddling with his new electronic nav computer, "We actually steer 078 deg magnetic" or thereabouts. The answer was obvious "Take a big packed lunch & we'll see you in a month".
I have not yet even seen a GPS unit in operation so maybe that scenario is no longer possible today. I'm just a bit wary of putting my life in the hands of a microchip. Or maybe I'm just too bloody old.