Yahoo data for both geo-information and satellite imagery for Australia is very out of date, effectively canceling out any application interface benefit they might otherwise have.
Google’s data for Australia is pretty much across the board and makes them a compelling choice in this space.

Like other commenters here, my feeling is that Yahoo has an unenviable amount of catching up to do. Perhaps they have another Yahoo text ads issue on their hands, where they’ve vastly misjudged timing and market.

I think that they main advantage over competitors is that they perform really lots and lots of user testing, which is something most web apps forget.

Even 37 Signals, on Getting Real dismisses user testing in favor of realeasing and waiting for feedback, which for anyone that ever tried user testing is just plain wrong. It baffles me every single time the amount of stuff I learn from just observing users.

I felt like Yahoo!’s interface loaded more slowly on a connection that loads Google Maps just fine. More importantly, I felt that while things were loading (expanding a direction step, for instance), sufficient feedback wasn’t given that something was going on. I thought I had broke it several times before something (a small inset map in that instance) finally popped up.

Also, I noticed that several times if I zoomed the map and then click-dragged it before the app was “ready”, the map would actually move BACK to the original zoomed position after loading the images.

Other than these few niggles (hopefully to be worked out soon), I generally liked it. Google will have to come up with something to match the whole left-side window they have going on.