Maybe I'll try a USG 3 port for the time being to see how I get on while waiting for the new releases. Don't think I want to use the VM router in anything but modem mode.
I took that approach as I am waiting on either a UDM Pro or ideally a new router only device so I can use a CK2 or one of my local servers for the controller.
I have the VM 500 service and also have inter VLAN routing for 9 CCTV cameras (recorded 24x7) and the USG 3 copes fine as long as QoS and IPS/IDS are disabled.