Flag MyGet builds as nightly, beta, alpah, pre-release
If the MyGet builds are marked as pre-release then it will be easy to move between MyGet builds for the same version number and also easier to upgrade to the NuGet stable build when it is released.
I deploy to Azure Web Sites which does the nuget package restore and full solution build for me. In order to move between MyGet builds or move to the stable NuGet build, I have to log in and manually delete the package cache on every site. If the MyGet builds had their own unque version number, upgrades would be easier.

To make it easier to upgrade we’re moving to an odd number versioning for pre-release MyGet packages and even number versions for official NuGet packages described in the release notes at:
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Jeff Gabhart commented
I'm not saying there needs to be nightly, beta, alpha and pre-release builds, just that one of those identifiers should be chosen and used to make the MyGet version unique.