I'm holding steady on v5 to Backblaze as the v6 migration path was promised post-v6 release, in June, and still hasn't appeared. And it also appears that support responsiveness has gotten worse.
I run backups on three Macs every 48 hours, then once a month or so I will use Carbon Copy Cloner to clone the two more important ones to sparse image files on a backup hard drive which is physically secured afterwards.