I've been using it for a while now, both to determine which peaks are in some of my pictures and to find out where exactly I was when I took them.
Today, I spent a long time figuring out some of the distant peaks on this picture:
I learned that the hardest trick is to find the location (and in this case I had to adjust the altitude that Google maps thinks belongs to that location) and the direction, using trial and error, generating lots of pano's. That can take a while indeed, but with the results it delivers, I can live with that! Fortunately, after that it's easy. Just make the size of the photo match that of the generated panorama and look real close.