When I bought BackUpBuddy I thought "I hope this works in an emergency".. so yeah, I too need to test the software under different simulated situations. It's always good to know the nuances of these things. I know BUB works similar to Duplicator, in that when you back up, a .zip archive of your database and theme are saved, along with an installer.php file for setting up WP in a clean server root.
I will be looking into UpdraftPlus. I do recommend Duplicator though. It is the free (and excellent) plugin used in the site back up/migration chapters of the PDF guide "Instant WordPress Unleashed". If you use Instant WordPress I recommend downloading the guide written by the author of the IWP environment. In it he uses Duplicator to show how to take backups of your site.