Git on Windows works fine for me, no cygwin in sight. It wouldn't have occurred to me to call msys 'part of a Unix interop solution', though I suppose it does give me a working version of Perl, which is a feature since it was the occasion for me to start using ack instead of grep.
Definitely UNIX interop, at least at the tooling level:
> MSYS is a collection of GNU utilities such as bash, make, gawk and grep to allow building of applications and programs which depend on traditionally UNIX tools to be present.
