TortoiseGit works fine too as long as you install it and Git for Windows with the OpenSSH option.
Tortoise Git is the only client that has ever corrupted a Git database on me. I don't trust TortoiseShellCache or WETF it is not to improperly lock the database.
Fuck the cancer known as PuTTY.PuTTY is great - as a remote login shell, only. plink is an abortion that should have been dropped long ago, and pageant should definitely support OpenSSH keys.