Update: Some readability issues and a promise for an updated review
Yahoo has launched Yahoo Maps Beta and instead of using AJAX they have used Macromedia Flash which is a very good implementation that utilises the Flex & XML features found in the new Flash product design suites. Sadly in my opinion the actuall navigation has some way to go. The system looked extremly clean and crisp which was definatly a joy to look at. Once the site first loaded I tried to get out of the San Francisco area it went downhill very quickly. Scrolling in and out with the mouse started to auto re-focus me for some reason, and do auto re-adjustments of where it thought my zoom level should be instead of my zooming and then Yahoo loading the pages of the map that are contained within my selected zoomed region I was trying to view. It appeared to do this when ever the maps were not cached/loaded within the flash object, which to me made it very difficult to use as if I did not zoom in then the application had no chance of loading the pages.
Having gone and fed the dog and hopefully New York city had loaded up in the cache for however it chooses to work it’s little Flash mysteries behind the scenes it still auto focused my zooming and it is just simply annoying. So if the rest of the features offered are good, I really will not know as due to those problems I experienced, I simply had no inclination to try as if I cannot look at the map in a standard way I am unable to try or experience anything better than that.
So if you use Yahoo Maps I would suggest you stay with the current version. I will still myself stay with Google as I have topographical and street maps.
Update: I will in the next few days add an update and review Yahoo again as it just may have been a bad net day when I was trying to use the system