Adam,
PFDAVAdmin started out as a way for me to teach myself C#. Originally all it did was fix non-canonical ACLs, but once I had that part done I thought it made sense to incorporate the ability to export/import permissions in the old pfadmin format. At that point, of course, it also made sense to have it do replica export/import just like pfadmin did too. I kept gradually adding features, and the tool gained such wide usage that it became an official release late last year. Now that it's an official tool, we do have a team of 3 or 4 people that maintain it.
Gphorx,
In the new version, you should use the Tools -> Set Calendar Permissions option to do this. The advantage of doing it this way is that it also automatically updates the permissions on the FreeBusy Data folder in the user's mailbox, as required by KB237924, instead of having to run a separate propagate operation for that purpose.
The only disadvantage is that it assumes that the name of the folder will be Calendar. For other languages, you'll need to use a custom bulk operation or the old propagate functionality.