As much as I like Google Maps, and I do, the whole "My Maps" thing is pretty non-intuitive. It was not obvious to me, how to dredge them back up after you had created and signed out and back in again, it was not obvious how to load a picture that could be accessed by your map. I also initially had trouble with the drawing tools, but that could just be me. After making a crudely drawn shape on top of a satellite map that included our library, I finally figured out how to upload a picture to Picasa and have it correctly link (just the picture not the album) to the shape on the match, I thought it was somehow saved. It seemed difficult to find again, and the map did not dispay at the level I though I had saved it at. Later when I went in again, it seemed to have totally disappeared, and when I attempted to create a new one, I couldn't get the picture (library layout) to appear.
So I gave up..... for now. I can see that it would be possibly handy to do quick maps with added features to add to direction pages, do maps of restaurants within walking distance of a library, etc.
The one thing this did remind me is that even for someone who likes new things, and generally embraces change if not wholeheartedly, at least without major resistance, if new and change can be a little frustrating for me, it could be worse for others.