Thanks for the list. I'll have to check some of these out. When choosing a software solution for enterprise it's also important that a product is actively maintained. That'd be a nice factor to add to this list.
Gotta comment about our fav, BackupPC. Your top pick boasts "deduplicating backup solution that features compression and encryption." Since BackupPC uses rsync over ssh and supports https it also share all of those great features. Put your data on a lux-encrypted mount and you're good-to-go.