My use case pretty heavily favors Duplicati + B2 over Backblaze Personal (OR crashplan home/family).
I have 5 computers all backing up into my B2 bucket now. 3 of them have ~5gb or less (mainly my laptops where all i’m backing up is personal files / documents / cherrypicked application configuration data etc). My wife’s laptop has her whole picture and music collections (~60gb), and then my main PC with my modestly large music collection (~120 gb all in all), and my relatively small media collection (mainly personal DVD and blu-ray rips, ~600 GB or so), totalling less than 1 TB across all computers.
So far this only costs me a few dollars per month in B2 storage, whereas with Crashplan Family it was in excess of $12/month. My media collection will inevitably grow, but it’s not going to suddenly quadruple in size or anything.