works great!
I had no crashing problems with google earth, but I always restart my iphone after installing a new app. Haven't had an app crash since I've got into that habit.
Google Earth works really well, though I was only testing it over wi-fi. I was also impressed at how fast the panoramio images pop up when you tap them.
I wish Google would make an easy way to import geotagged-flickr photos into panoramio, or that they would just allow geotagged flickr photos to appear in google earth. Don't want to have to move my photos from flickr to panoramio.
As for the "what will I use this for" question. . . probably just entertainment and showing off. It's free, and awesome. You can look anywhere on Earth at any time, and now you can do that on the bus.
Man sometimes I'm just amazed at technology. Imagine telling someone just 100 years ago that, in 100 years, they would be able to hold a tiny device that allows them to view the entire Earth, completely photographed by orbiting spacecraft, in the palm of your hand. Amazing.