it's a fork of PuTTY with a portable mode which stores everything inside a .ini file. It's amazingly easy to move/backup/etc.
But it has not the newest security fixes for putty :(
PuTTY was only updated 6 days ago...so I don't find that terribly worrying for a fork. The update history for KiTTY seems to imply it would get updated soon.[0] e.g. the .69 and .70 updates were merged within a few weeks the last time...