I am not a typical user, so my views might be a different. I am mostly installing and configuring the system for customers.
If you run a Linux server, the software will be setup in a few minutes. All standard configuration can be done suing the GUI. The system support multiple tenants/publications which is great since you can use the same system for different organizations.
The software is 100% Open Source and free.
I found the GUI pretty much self explaining. So I didn't really need the standard user manuals.
I like the fact, that it is based on common GUI standards.