Which Tool to use to create a NetInstall Image?

1) The Casper NetBoot Automator Action is a workflow for System Image Utility. It's old and I don't believe supported any longer.
2) The NetInstall Creator had been deprecated (back when it was NetBoot Creator) but was recently revised and updated. If you've never created a NetBoot image, start here: https://jamfnation.jamfsoftware.com/viewProduct.html?id=13&view=info
3) In the timeframe between the old NetBoot Creator and the newly-reintroduced NetInstall Creator, there is a manual process (that had its own Knowledge Base article) about creating a new NetBoot image, enabling the root user, and using System Image Utility. Obviously this is the most flexible method, as you can put other tools (disk repair, data recovery, hardware utilities) on a custom image.
4) There is also @bentoms' AutoCasperNBI, which is a bit more customizable than the NetInstall Creator, but it's in beta: https://jamfnation.jamfsoftware.com/discussion.html?id=11356

Again, if you're totally new to the process, I'd start with NetInstall Creator to build your first image. You may then want to try AutoCasperNBI, and creating images manually (lot of manual steps, easy to miss something).

I hope this helps clear up some of the confusion regarding these utilities.

I recommend @bentoms solution, AutoCasperNBI. It is new but I think he is doing a great job with it and it is likely to have the features you are looking for. https://jamfnation.jamfsoftware.com/discussion.html?id=11356

I am using System Image Utility to create a NetRestore image from a Macintosh HD setup with 10.12.6 + Apps. For whatever reason, I only get the option to create a Netboot image?

I am using a VM, 2 disks with 10.12.6 installed. Booting on Disk1 to capture an image of Disk2. If is mount a USB with bootable 10.12.3, System Image Utility gives me the option to create NetRestore of this USB mounted macOS, but not giving me the same option for the 2nd disk.

Am I missing something?

I believe Apple is going to discontinue the ability to NetBoot in the near future or new Macs though.

Stop Now Please. Learn about startosinstall ,recovery and thin provisioning

msmith80 writes: "I believe Apple is going to discontinue the ability to NetBoot in the near future or new Macs though."

They already have. No Mac introduced in the past year supports NetBoot. It's not a big stretch to imagine no new Mac introduced from here out will support NetBoot, but it's possible some will. I certainly would not make any plans based on the assumption that any new Mac will ever again support NetBoot.

wish jamf would get on board and introduce supported startosinstall workflows. it's sad people are still wasting times trying to make netinstall work & jamf is spending time supporting it.