I've been using DropBox for a few years now. I like it a lot, but its not a real back-up solution. Its just a way to store and share lots of data. I do like that I can set it to save the pix from my phone automatically, and that I have a copy on a physical drive here at home and not just out there on a cloud.
I also started using BackBlaze a couple of months ago. Seems fine. My purpose is to back up my PH FLAC collection, and (knock on wood) I haven't had to use it yet.
Terry