I have a question about post-installing OSX... Is it better to a) treat it as new and re-install apps and re-copy the data over from an existing backup b) Use the user migration to pull users (and applications) from existing backup Option b would definitely be easier. But would there be any advantage to option a? I am seriously thinking about doing a full clean install of Mountain Lion on my iMac. It's three years old and been through Snow Leopard, Lion, and now Mountain Lion. I am thinking a clean install might boost performance a bit.