I never found it to be overly reliable. It was reliable... for a while. Then would silently fail/stop working, or just tell you that it had stopped working and that whatever you had in it was no longer accessible.
And then I went to Acronis True Image backing up to my Synology NAS, but that became unreliable too - oftentimes when I'd go to do a restore, the client would crash trying to read the catalog.
So, like you... CCC nightly to my Synology, with a Snapshot rotation on it - snapshot the previous night's backup at 8pm, and then kick off that night's backup at 11pm.
It was unreliable over SMB. Not surprising when you look at what it was doing. It would create a virtual drive on the share, map that and backup to it. There was too much going on for that to be reliable.
loading story #47932402
For me it was a key DB file inside the Photo library which Time Machine omitted from all backups and prevented me from restoring the library. Not fun.
Yeah, you may be right. I have fond memories of it from around 2008, but those might be from the initial experience and not all the "you need to recreate your back from scratch" errors that would crop up after a while.