Just finished implementing a network backup solution for a customer using Bacula and reached these comclusions:
Bacula is hard. But that is mostly because the problem is hard. You need to backup 30 different computers over a net, in a secure manner, with different data sets for each... well, it is going to involve defining 30 datasets and so on.
Bacula is very good. It supports VSS, which alleviates the classic windows "that file is open you can not read it" problem.
Backing up Windows sucks.
It is pretty hard to know what to backup exactly to catch all configs and user data. Not so much on XP, but on older versions... yikes.
You pretty much can't ever be sure you are allowed to back up everything. I have a fileserver with files the local administrator can not read. So, it seems a user can create unbackupable files!
I still need a decent system backup for Linux. I have used Mondo for a long time, but it's a pain in the butt, and it's getting more painful as time passes. I want something that I call and I get a nice DVD with the whole system in it. If you have a suggestion, please drop a comment ;-)
A system that automates the backup policy as much as Bacula does is great. Except that it makes it quite hard to guess the exact amount of storage (I am doing disk-based backups) you will need.
For simpler stuff, you should use flexbackup. Their slogan is amanda is "too much", and tarring things up by hand isn't nearly enough and it pretty much is what it does.
For personal stuff, rdiff-backup is awesome. I really should write a graphical tool for it one of these years :-)