Everyone's backup requirements differ. What works for me may not work or be pointless for someone else.
I'm sure a lot of people can get by with Mozy or Carbonite because they mainly browse the web, and write an occasional Word document or two. Others have more data and are better served by going with multiple tier backups.
There is always a third way of doing backups. A service like Box or Dropbox. If one uses it to stash their documents, then if their computer gets destroyed/stolen/fried, the machine can be replaced, the OS reloaded, applications re-downloaded, and the documents be available and ready to go. However, this may not work well for others.