You can now have many different content types each with a seperate set of custom fields, each with a seperat set of templates and each with a different set of ACL's.
So no need of cloning Sobi2 anymore.
It's not just a directory component, it's a content construction kit (CCK).
I can not imagine anything that can't be done with SobiPro.
I business directory, an ads platform, a plant or animal database, whatever you can think of. I personally plan to realize a fish database with it. I like SobiPro so much that I decided to start developing some plugins (fields) for it.
I get very good support from the dev too. Its real fun.
The developement goes on quick and new fieldtypes are developped quickly.
SobiPro is one of the most versatile Joomla components ever.