In case people still have issues with downloads I created torrents for windows and mac versions.
If you already downloaded a binary you can help seed.
kicad-5.1.0_1-i686.exe.torrent (21.6 KB)
kicad-5.1.0_1-x86_64.exe.torrent (21.6 KB)
kicad-unified-5.1.0-10_14.dmg.torrent (23.5 KB)
kicad-unified-5.1.0.dmg.torrent (23.6 KB)
Here are md5 checksums:
$ md5sum kicad*
f70478c4de8597db9402b2517cafc89c kicad-5.1.0_1-i686.exe
15a37828a81a4102cb0aaff50779696b kicad-5.1.0_1-x86_64.exe
f392321af0513a5c6920bb89ca7831c7 kicad-unified-5.1.0-10_14.dmg
923c7107d8479d340a0a663f87a32441 kicad-unified-5.1.0.dmg