Snapshot is considerably easier to set up than the other program using.
it has the ability to limit how many local copies, you'll keep. But it doesn't seem to give a damn about how many copies it keeps on your cloud.
I have a little problem getting the Cron to run right. And when I looked on Amazon's S3 account. There was 15 backups in there that had been queued to never ran.
As far as I can tell there is no way there is no way to limit the number of backups on the cloud.
That certainly should be a feature request if it's not possible in the present code base.
I've been using BackWPup for about three years and it's been very reliable and very flexible. Which means it's hard to set up and run and get all the variables right. It works with many if not all the clouds.