In reply to jaswa:
>>After all i think that they are accurate to about a meter or something aren't they?
Depends . . . about 6m (ish) in nice weather with a good view of the sky, noticeably more wobbly under even fairly light tree cover or round the bottoms of crags. Was out after a cache at the Roaches last night, and knowing which route I was looking for was more accurate than the GPS.
(I am saving the one on Slanting Buttress for cache #1000. Done the route before and never even knew it was there.)