I'm going to write a quick review of the good and bad points of each mapping software as I am checking them out.
Again this is based on what works best for me so far which is Google maps using Terrain view.
I've heard people recommend the Harley Davidson Route planner, found in the tools area of the HD site.
Advantages: direct communication to and from gps. You can type in an address and add waypoints by dragging the route.
It has user added routes recommending good roads, Harley Dealerships, Best Western Hotels and HOG events. This is an advantage to both Harley riders so they know where the parties are located and non Harley riders so they know where the parties are at and can avoid them!
Disadvantages: Really slow interface on my computer, especially if you have the "show user routes" enabled.
Uses Google maps Road and Ariel or mixed view but no Terrain view so it gets a thumbs down from me. It also seems to gets easily confused when you've created a route and added waypoints and then try to delete a waypoint or tweak the route. After deleting a waypoint I still get old route remnants and can't make them go away.
Google maps still in the lead for me since I have to have Terrain view, although I'd love to have direct communication with the gps.