A coworker wanted a copy of my development VM so I SysPrep'ed it and gave him a copy of the VHD. There were two challenges.
First challenge was that my VHD is a differencing disk so I shutdown the VM and used "Edit Disk..." to Merge to a new VHD file. This worked out well because I wanted to leave my original VM intact so I left it turned off and created a new VM using the new VHD to run SysPrep against.
Second challenge is that SysPrep failed with the error, "A fatal error occurred while trying to sysprep the machine." KB article 2769827 explained that the built-in Windows 8 apps were the problem. I logged in as the Administrator user and deleted my domain user profile.
Running SysPrep a second time worked fine. I shutdown the VM, gave the VHD to my coworker, deleted the VM, and started my original VM to continue my development work.
Note, for safety you should create a checkpoint in Hyper-V Manager before turning on the VM to run SysPrep. That way if you encounter an error like I did you can Apply the checkpoint to revert to a good state.