I had a similar experience with Bikeroutetoaster. Found out about the site and gave it a try mapping 25 miles of a longer route that I am familair with and then making a cue sheet. It missed one turn completely and labled another a left when it really is a right.

As for MayMyRide, the elevation numbers are notoriously inaccurate. Some call it "CrapMyRide." The recent Grand Fondo in Philadelphia used it to map their routes. I looked at the century map and, being familiar with the roads, said "No way is there only 4,700 ft. of climbing." Tunrs out it was 7,000 ft.