I do several backups over FTP. A backup program I see get little mention is Ease Backups ( www.kiesoft.com ). I have tried all the backups programs mentioned and I find Easy Backup to be by far the best if you intend to backup to an ftp site:
Why:
1. It can do patch backups which will reduce the size of the backup greatly especially if it involves large files that change little.
2. It can handle slow unreliable links. It just keeps trying. Anything that it cannot upload will get quede up for the next attempt.
3. It can handle having a time limit so that you can say backup from 10pm to 6am and if you cannot complete continue in the next session.
4. The log file it sends it not the most human readable but it has all the info you would need to figure out what happened. I have a script that parses it in pocomail to produce a simple report of what got backed up and what was skipped for lack of time or because it was in use.
5. It brings a driver to handle open files although the driver cannot overcome files that are locked because of network access.
6. It can handle unlimited version backups and because it uses patch backups as an option keeping those versions does not consume nearly as much space as a traditional "keep another copy" type backup
7. The UI is pretty good. Some of these backup solutions I find try to get too cute in the UI department.