I prefer doing system backups with dump. Like that:
dump -0 -z9 -f root.dump /
I've stored the images at a internal FTP server. If for instance server a's HDD died I just put in Knoppix CD, reboot and get the images from the FTP server and then create the partitions and restore. That's easy and saves a lot of time ...
You can't use dump for a all-the-time backup though. Like I created a image once the systems were set up completely and then creating checksums on the dumps (to verify integrity). Now I backup just variable files (configuration files, logs, etc) using tar.