I've never needed to restore anything, so can't say anything about this, but once, one of my devices deleted a file in Syncthing, and I went into Backblaze to see if they have any logs of deletions/file modifications (had it disabled in syncthing).
I don't remember the exact details, but I remember clearly that I felt like the entire thing was done by a junior engineer straight out of college. Trying to understand the names of some variables used there, I stumbled upon a reddit thread where the person who worked on the client was trying to explain why things were done the way they were - and I felt like it was me in my first 3 months of software engineering.
How did Backblaze gain this trust in the first place? Is it because nobody is offering "unlimited" storage at the same price point?