Yes mate.. lack of autogen if you add your own photo tile is the main drawback though I'm told that adding your own isn't that difficult.. not that difficult if you happen to be GeorgeD!
I did muck about with autogen annotator a while back on Jersey (already had a photoscenery background for it) and added some trees in a "treescapes" style, but the buildings wouldn't show up properly. Must have been doing something wrong, but couldn't really be bothered to follow it though. If anyone wants the trees they are more than welcome.