Well.... when I gave it my address for a starting point ... it it DID locate me on the correct road .... 3.75 miles down the road from the correct location! Gotta wonder about that...
Also note that when you click two points, it always assumes "as the crow flies" .. it doesn't acutally follow roads.
I think I'll stick to Delorme Topo USA to plot routes and an Excell spreadsheet macro to gen bike-friendly cue sheets.