While caching with my Vista, the map helps alot, especially if you aren't familar with the area. I can zoom in and look for roads to take me where to park, etc.. We did 3 caches last weekend, one it was nice to see where the turns were, but we would have found it anyway, on two, was only used for the cache, so no big deal with the map, on number 3, without the detailed map, we would not have been able to get even close to the cache. As for the base map, I find it almost useless, no details, no streets, several of the highways we were on did not show up, and I like to see the names of the streams and small lakes that the base map will not provide. Oh, I am using Roads and Rec, and will be getting metroguide.
It's not a sport unless there is something dead in the back of the truck when you get home.