I couldn't find a proper database for my current project, until I started looking at object databases.

There are many: https://en.wikipedia.org/wiki/Comparison_of_object_database_management_systems

Anyone has good experience using one of these as a central data storage for complex objects? (thus not as embedded db)

I tried several but I don't know if this works on the long term. What if your data model changes, do you enter hell? :)