I use Arq to back up to Dropbox because I have the space there. It works fine, but the main annoyance is that you have to remember to use Selective Sync to not

I use Arq to back up to Dropbox because I have the space there. It works fine, but the main annoyance is that you have to remember to use Selective Sync to not sync your backup folder to any of your desktop computers linked to Dropbox.