Keep in mind that most "unlimited" backup systems have one or more gotchas. Like:
* horribly inefficient clients written in java
* annoying retention policies
* limited compatibility, often no linux
* bandwidth throttling
* IOP throttling etc.
* horrible restore times
However if you skip that an pay as you go you typically get much more control, much more compatibility (including linux), and much better performance. Like say using S3 or Backblaze's B2.