One other benefit of using a GPSr to navigate that has yet to be mentioned is that particularly in bad conditions, it is much quicker than using a map and compass to navigate. On pathless ground or snow-covered terrain in mist, with a howling wind blowing there is no contest between a GPSr and navigating by multiple short legs or leapfrogging with pace counting with a map and compass, it is much quicker and less error-prone. If you have pre-loaded the GPX track that you intend to follow, it's even more speedy to check where you are on the digital map, which direction you want to go and the next feature you should encounter.
I'm with Ninthace in much preferring the new technology on a dedicated outdoor GPSr, but I still occasionally practice with map and compass to stop my skills becoming too rusty. My Garmin then helps me work out what sort of positional errors I'm making e.g. timing over/under or pace counting short/long, drifting downslope on a traverse, etc.
Why not use both tools and become 'bilingual'?