Just wanted to make a few comments. I have owned a PN-40 since December and have found over 260 caches since then with it. I am very satisfied with its accuracy, particularly under the tree canopy. Prior to the PN-40, I used a Garmin GPSmap 60 - no color and batteries lasted about 16 hours. I use Energizer rechargeable batteries, two in the unit and four in reserve. That's get me through a long day of geocaching.
I use GSAK, Cache Register, and Topo 7. Most of the time if I see a cache that I want to find, I use the "Send to GPS". I have also found that rather than having 500 caches in a PQ, that I prefer to have 50-75. That makes it easy to set up one or two cache runs.
I still use my old Garmin Streetpilot C530 to take me to the area then use the PN-40 to find the cache. I like the large screen on the C530. It's a lot easier to see than the PN-40 when you are driving.
Don't forget to download the Firmware 2.6 update.