I was a Beta Mozy user about two years ago and, up until August 2009 I found the backup service to be reliable and an excellent value.

Something has gone terribly wrong with this service. Maybe it was coming with it being part of Decho...but the backups became erratic in late August 2009. Server connections would drop for no reason, errors like "User account in use," which they do not explain on the site. On one incremental it would report that it was backing up a few GB, other times, 20GB, other times 60GB, or even more. With few changes being made to my system, why would an incremental backup vary between 1% to 100% of my entire holdings?

Tech support and escalation support have been working with me but they keep trying to roll out new versions of the software....which requires the deletion of backup configurations, which take time to recreate.

Worse yet, I had a few hundred GB backed up, and simply disappear from their servers....at least when the backups were having problems, I knew that most of my data was still in their possession.

I don't know if it's the software or the servers they are probably contracting, but I have to go back to old fashioned hard drives and bringing them offsite periodically. Carboninte does not support external drives, and simply backing up a Mac laptop internal drive is not terribly useful.

Does anyone have experience with Amazon S3? There are client applications which use this service.

USED to be a very satisfied customer. Not any more.