I moved to Acronis True Image when they offered unlimited cloud backups with their 2016 version. They probably couldn't sustain it, because I had to pay a lot more for backups when I wanted to renew in 2017.

Now, I'm using both Arq and Synology's Hyper Backup with Amazon Cloud Drive. One of the problems I foresee is that while Amazon doesn't care how much data one stores in Cloud Drive, they have suspended users for downloading past an arbitrary limit in a certain period of time — so full restores might not be possible.