Update 2 : I've now enabled "preliminary" support for Retina mode in Yummy FTP (and sub-apps) for the next update

This means that while most of the app looks great there are some icons that will need hi-res versions and/or some drawing glitches, but for the most part Yummy FTP works just fine in Retina mode and looks pretty awesome too! It's certainly a ton better than the fuzzy mode

I will address any remaining issues with further update(s).