I used Backblaze B2 for a project as the store of the files.

I had to switch to elsewhere once hitting production, when doing thousands of async upload requests, some would randomly 403 on me. Their customers rep solution was to handle it on my side (yeah, I know) but it was easier for me to just switch providers.

I guess for other products Backblaze is good, but I wouldn't recommend their Backblaze B2 to other fellow devs, those nines of availability in difference are noticeable on the long run