Users on xda-developers are using the client to maintain a local copy of large repositories that house all the changes to the rom they are using. The main advantage is to download the bulk once and then only the changes. Export is preferred to checkout because the .svn meta data interferes with the process of getting the rom ready to flash.
I want to ensure that if you do an export of revision x and then want to "update" that export by doing another export of revision y that the only the differences are downloaded, etc.
This investigation might lead to an improvement or new feature.