windows server backup = works but is basic. Notifications are a mission to setup with task manager and they don't always work. Individual backups for each server setup on each of said servers
Paid Solutions = centralized setup, client gets installed on servers and managed from one place. Notifications are a breeze and restores are easily done from management server.
At the moment Windows server backups are used, it does "work" but is a hassle to maintain and make sure that it stays running...