The one big plus for ucs is their samba server, but it's not the right choice if you are looking for an appstore to install apps from.
My personal favorite is Cloudron, as they have an app concept that only needs minimal human maintenance. And you could even combine it with an LDAP server like ucs for the user management.
Similiar and a little bit more mature is also YunoHost, https://yunohost.org/, or for professional environments, UCS https://www.univention.com/.