Snapshots are a convenient point-in-time image of your whole server AWS vHDD (similar to a snapshot in VirtualBox or VMware). They can be handy but are large (they include the whole filesystem) and are only available in AWS. They are not a backup replacement as things can go wrong with snapshots and they may become inconsistent due to disk-buffering and locking.

TKLBAM is a smart backup and migration tool that runs anywhere. It doesn't care if you are running in the cloud or in VirtualBox on your desktop. It is designed as a backup tool and generally has very small backups (obviously depending on the size of your data) as it doesn't backup the whole OS; just the important bits!. Even though it is purpose built backup system you should still test your backups regularly to ensure that everything you need is included (it's smart but it can't read your mind...) and restores work as they should (we try hard to make it as robust as possible but bugs sometimes happen).

I hope that helps...

Here are some links for further reading:
Snapshot Blog announcement: http://www.turnkeylinux.org/blog/hub-snapshots
Original TKLBAM blog announcement: http://www.turnkeylinux.org/blog/announcing-tklbam
All blogs tagged 'TKLBAM': http://www.turnkeylinux.org/blog/tklbam
TKLBAM docs: http://www.turnkeylinux.org/docs/tklbam
TKLBAM FAQ: http://www.turnkeylinux.org/faq/backup-and-migration-tklbam