Zawodny says Yahoo updated their satellite imagery, and gives an example of a remote airport where the images are higher res than Google's. I've seen similar differences between Google Maps and Microsoft's Live Local, with each service stronger in some cities than others. It's the same for Yahoo and Google.

I zoomed in on my own neighborhood in Yahoo and Google, and in this case Google's satellite images are far superior.

On the left is a 300 x 200 pixel screen shot from Yahoo at its highest zoom level, and on the right is the same size image from Google's service. In my neighborhood, Google's imagery is clearly superior, you can easily see cars and read street markings in Google.



Interestingly, Microsoft's Live Local seems to have the best imagery in my city -- you can view the same spot from four different perspectives, and zoom even tighter than Google and much better than Yahoo.

I'm sure somebody's done a more thorough and scientific comparison of the services, but I haven't seen it. So until then, to each his own.

As a Google investor, the back-and-forth on features is fun, but not strategic. What's important is that Google is known for innovation and leadership, while the others take months and years to copy Google's strengths.

And what's really important are the things competitors can't easily copy -- Google's massive infrastructure, its deep pool of engineering talent, and Google's brand and reputation.