There are still a few issues with this module that need to be sorted before it's really ready for production use.

There is no distinction between addresses saved on the user profile page and ones saved at checkout. There needs to be tighter integration so duplicate addresses do not occur.

There was something else but it's late and I can't remember exactly what it is.

I hope someone can pickup this module and do a little work on it because I'm so snowed under at the moment.