I always use proper maps and always will; why would you want to use a GPS? You might as well read the map through a cardboard tube as you'll miss the general topography, the places of interest nearby and all the other fascinating features a map shows you.
Example: planning a trailquest event: how does GPS show you the general lie of the land over a big area like the North York Moors? In order to plan your route you need to see the river valleys and the hills so as to understand why the high-value checkpoints have been placed where they are then make a decision as to whether you will go for long distance and high value or stay local and bag lots of low value checkpoints. Maybe you can pre-plan this and download it into a GPS but how does the GPS cope with contingencies? Your major objective becomes unattainable for some reason so you decide to cut and run for the overnight stop, picking up a few low-value en route and avoiding time penalties. Only a paper map can give you the big picture that enables you to plan at such short notice, especially when minutes can become penalty points.