While you have the ability in BRU to create user accounts that they could use for logging in, the really bad thing about BRU is that any user account can browse the the list of devices configured on the server as well as any backup files regardless of the user that originally put that info there.
The BRU Server Console is an extremely frustrating user interface with a lot of “quirks” that will make it a big headache for tech support. Also, there is no Windows client for the BRU Server Console, so Windows users would not be able to restore their backed up files.
Time Machine has some nice capabilities, but Apple is adamant in my conversations with them that TM is not for an enterprise environment. So if that’s not you and you aren’t worried about encryption of sensitive files, it might be a better fit for your Macs. It will not of course solve your backup dilemma for Windows computers.