If open source isn't a requirement and you want a polished GUI client, https://www.bitvise.com/ssh-client has been free as in beer for about 1.5 years. It will be tough for them to beat being part of the default install!
Bitvise sells a solid Windows-friendly SSH server for $100. I am not affiliated apart from being a happy user since before OpenSSH supported AuthenticationMethods (multiple required) in 2013; it has been my straightforward licensing alternative to Remote Desktop Gateway.
Odd licensing (free for up to 4 users/machines, but crossing to 5 required $45/seat) really crimped adoption before the license was changed. https://web.archive.org/web/20160329203117/https://www.bitvi...
Bitvise sells a solid Windows-friendly SSH server for $100. I am not affiliated apart from being a happy user since before OpenSSH supported AuthenticationMethods (multiple required) in 2013; it has been my straightforward licensing alternative to Remote Desktop Gateway.