@tylerloch Possible it could be related to Dell's SafeBIOS:
Rather than storing BIOS and Firmware information on the hardware itself, which is susceptible to corruption, Dell SafeBIOS delivers an off-host BIOS and Intel ME verification capability.
If you need to support secure boot, you'll need to use the windows imaging environment. Other than that you need to disable secure boot, image, then reenable.
@theopenem_admin Thank you so much! After the last two days of testing and use, I'm seeing speeds saturating my gigabit connection.
And reliability is now rock-solid. Before, creating images was extremely stressful, as timeouts and errors would happen more often than not, with no obvious notice. I can now create images without worry.