Techcrunch has a good review by Frank Gruber of the look and feel of mapping services. I think it is notable that ESRI's service is not included in the review. I think it is at least as good as the mapquest service. I may have to find time to redo my review of the acuracy of each again and a more technical evaluation of each.
Good Techcrunch review of mapping apis
By carson | Published: April 18, 2006