We use the XML export/import facility all the time. It is particulalry useful in getting data into a second temporary (local) installation when we don't have access to our servers for admin purposes (e.g. when we're onsite at our clients and behind a firewall, which is 99% of the time). What's really inconvenient is that the attachments do not get included into the export in any way. Some way of getting these through to the client (e.g. zip up the directory and download to client) would save us a lot of time.