Yahoo Maps is muchly improved, with a user interface that is much, much nicer than that of Google Maps. The Google product seems stodgy in comparison. And, all its interactivity works with the Opera Web browser.
I find Yahoo Maps faster than Google, especially when displaying satellite images with roads overlaid. Yahoo Maps also knew my home position, where as Google doesn't.
However, some data is missing from Yahoo. For example, it could not find the Comfort Inn in a city I'll be in this weekend. OTOH, Google cluttered up the map with dozens of other hotels markers, so that I could not spot "my" hotel. That's because it was listed as "A" and because it was first, it got overlaid by all the other hotel markers in the area.