First of all thanks again for creating this plugin, it's very useful.
I have a few questions and suggestions.
Could the manual backup be a button, instead of just the URL text?
Could it show the progress of the backup, or at least some sort of feedback that it's running?
If anyone else types in the manual URL, would it also trigger a manual backup, or only if that person logged in to WP?
Could there be an option to send a notification email when a backup is done?
Can you explain what does the option mean that says: "Select never if you want to add a cron job to do backups" ?
What would be the process of doing a cron job, and why would someone need to do that? Isn't that what this plugin doing already, when it's running a schedules backup and uploading it to Google Drive?
Can the archive file name be more descriptive? Right now it says: 1339720169.zip, could it be WP_2012-06-15 or something similar?
What happens when the maximum number of backup is reached, does the oldest one gets delated from Google Drive?