Well I've been using the WAAS capable Delorme Earthmate with Street Atlas on a PC and it works well when it comes to position updates on the screen and when it pans across from one grid to another. I don't have a stand alone GPSr like say a Garmin 60 to compare the two setups, but I've read an article a while back that compared PC based GPS systems and standalone receivers; The author concluded that a standalone receiver is noticeably slower when it comes to functions like zoom in, zoom out, pan and toggle between different views. This was one of the cons mentioned apart of course of the smaller screen size and memory. I'm contimplating purchasing a car mount for my laptop, but I wanted to hear what others' experience been like before I do so. Standalone GPSr have lots of pros, but I mentioned some cons to make a point. They're both great devices though.