Mirrors of Voyant Tools
The main server of Voyant Tools is located at voyant-tools.org. In some ways it's the most reliable server to use (though it gets the most use and is subject to occasional performance issues and sever outages). It's also likely to be the most up-to-date version since new builds are deployed there first.
Having said that, there are good reasons to use one of the mirrors, particularly for geographic proximity (the main Voyant server is hosted by ComputeCanada in its eastern Canada cloud).
Known Mirrors
If you're interested in mirroring Voyant, please let us know by submitting a ticket on the VoyantServer Github!