Just a correction @RBM for future readers, so that we do not mislead.
Hifiberry RoonReady image is loginable now. U:pi, P:hifiberry.
It is a Debian/Jessie build, so… $ sudo raspi-config for password change.
Be advised to use latest 1.2.1 image: http://downlaods.hifiberry.com/images/roon-1.2.1.img.zip, as 1.1. has a bug where some devices do not show up in Roon.