In my experience, the basic backup utility is the most effectivy & can back up to network volumes if they are setup as shares. Let me explain why...
The backup utility built into Microsoft Windows Servers writes events to the system logs. It records an event when it starts, it records an event when it finishes, it records an event when it starts to verify & it also records an event when verification fails or the backup fails. This gives you accountability and a record. It also works with the replication of critical domain features and if you are familiar with the logging, you will see events like 'have not been backed up in 90 days'. Using the 'basic' backup utility will get rid of these events also so you know, and according to microsoft you are doing your job.
It can also be run as a scheduled task and will write to the logs when the scheduled task fails.
Also, on ALL Microsoft workstations there is a default administrative share to the drives on all hosts. Such as the C: drive! \Hostname\C$\ or \Hostname\D$.
The only thing you need to decide on is a push or a pull? Are you going to perform the pull on the host with the iSCSI disks? Or are you going to push from the host with all your storage to your host with the iSCSI disks?