Does the GH Enterprise option not provide some degree of support with initial setup and configuration? Is the enterprise support more or less responsive than the public channels? I would expect those same engineers are also responsible for maintaining the enterprise offering.
Also, does isolation of a private GH instance from the public instances not provide some degree of added reliability considering the potential for DDOS or simply extreme load?
I absolutely grant you the IT infrastructure concerns. BUT Amazon is our vendor on that. GitHub provides the software. It's not like I'd be standing up a new series of physical hosts to run an on-prem GitHub built from source and managing all of the hell around that. This would be simply putting a GH-provided image on a EC2 instance and making sure we have frequent snapshots.