Never used a GPS in my training even though the aircraft were fitted with them. The instructor used them, but not me the student. All my Nav training was conducted with DR nav and 1 in 60's using the CR2 to flight plan.
Didnt use a GPS till first job and i still use GPS only as a guide, still carry maps and navigate holding a heading and position fixing. Best thing though about GPS is you can keep climbing until you find a tail wind, so save the boss some money and if you have to divert due weather its a much quicker safer way to get going.
Never rely on it though, its just an aid to your VFR nav skills.
4S