Backup Manager is designed for both server and desktop applications, it's easy to configure, use and is fully automatic. The reason that it's a command line tool utility is that it's setup to run daily via Cron without intervention from you NOT because it's for advance users only.
Backup Manager uses only open standard formats: tar, gzip, bzip2, lzma, dar and zip. This means that you can open your backup archives using any standard archiving utility even on different platforms without having to rely on Backup Manager.
When it comes to regular files, Backup Manager can be set to run full backups or full / incremental backups. MySQL and Subversion backups are always full dump.
Backup Manager features a Generic Backup Methods which can backup almost anything. You can even use it to connect to remote hosts and backup that host's files or database.
Yes, Backup Manager can be set to upload the resulting backup archives to remote location via SSH, FTP, RSYNC and can even upload to Amazon S3.
Using archive encryption and/or SSH network transfer, but you have to enables these security options in the config file.
Maybe. Check your package management application. If it's an old version you're advised to manually install the latest release. Manual installation is straight forward. Check Installation for more info.
Backup Manager provides and external hooks feature which lets you run scripts before and after a backup is run. These scripts are often used to mount and dismount drives. Check the External Hooks section documentation
Naturally your backup device will be another hard disk on your system or a network share. Either way you will need to mount the backup device in your file system. Suggestions include:
Backup manager need a few paquages to upload to Amazon S3. You have to install libfile-slurp-perl and libnet-amazon-s3-perl perl libraries.
Backup manager stores the backup files in open format like tar, dar, etc. Almost all distros have the appropriate command line and GUI tools to extract the backup files.
If you want a text based GUI to use from the shell try Midnight Commander. It's available in almost all major distros by it's shortname mc. It's a complete file manager that opens all major archive formats. Note: It's been reported that Midnight commander might have problems opening huge 20 GB + TAR archives. The command line tar command does not have this issue.
These files are built by tar itself when creating incremental archives. Tar uses those files as a catalog in order to remember which files changed since the last archive was made.
... To be answered!