Interesting that the build instructions refer to Cygwin. It's a bit surprising, I'd have expected something more native. What does this bring to the table that regular Cygwin OpenSSHd couldn't do 10 years ago?
Powershell integration. Cygwin SSH drops you into a bash prompt running on the Windows box. Powershell is much more deeply integrated with Windows, and is more useful for actual system administration (e.g. configuring IIS, SQL Server, etc) than Cygwin's bash.
What "integration" are you seeing? It looks to me like they're just dumping you out to a CMD.EXE instance and leaving it up to you if you want to run Powershell. It's nice to see MSFT embracing SSH and all, but this is nothing that we haven't already been able to do for going on 10 years (likely longer) w/ OpenSSH on Win32.
But cygwin seems to have v7.1 too. Is it "just" a build that doesn't depend on cygwin.dll? (Although I can appreciate that's probably a nontrivial porting job). Genuinely curious about what's new here.
It's an early alpha build. This is "just" getting to a point where they're working on a modern codebase. MS has said that they're going to add more functionality as they develop this into a much more useful admin tool.