The reason I got a GPS in the first place was because I got lost in the last 10km of a 200k audax. I realised there are two aspects to being lost - first, you have to work out where the hell you are, and then (and only then) can you work out where to go next.
At night, in trees, a map may well not be able to tell you where you are. If you don't know where you are, you don't know where to go. A GPS can at least tell you where you are, and most are then capable of telling you where to go [sic].
It was only after I got one, that I realised you could turn it into an electronic version of an audax routesheet that would light up and beep at you when a turn was approaching, even in the dark bitter watches of the night. This aspect may or may not be important to you, but it has saved me from many extra km - not to mention the discomfort of having to wear a headtorch all night.
My GPS crashed this weekend during a ride, and on reboot, it dumped everything I'd programmed in. From that point on, it was of limited help.
It has never been a hindrance; only a help - say 3 to 9 on a scale of 10.