eSyndiCat is more a directory software or catalogue of whatever you wish, there are two main concepts in it - Categories & Listings. Basically is could be used for whatever you wish, but the main aim is to be a directory software for the links or listings that have URL.
Subrion is more a general style CMS. It can be easily used for different types of websites + it has some extra functionality like Responsive Administrator Dashboard, Automatic Upgrades, more flexible core (you can get the list of features here: http://www.subrion.org/features/ ). Its functionality is developed with so-called packages in mind- Extra feature-rich plugins that extend the default functionality of the core. For example, now we have 6 packages - Web Directory, Publishing, Auto Classifieds, Realty Classifieds, Yellow Pages, Coupons. We are developing our core system like content management framework so anytime we could start developing a new product easily.
In terms of features - esyndicat is better now for a directory, but if you need extra functionality for the script - like community features, Subrion should be your choice.