First up with RebeccaBlackOS, they have changed the base operating system from Ubuntu to Debian Testing. Moving away from Ubuntu was done to avoid licensing issues, "To comply with Canonical's new licensing requirements for Ubuntu."
Rebecca Black OS also now has EFI bootable support, is powered by the Linux 4.3 kernel, has KDE Wayland as a usable option, improvements to the login manager, and more.
The 2016-02-08 release ships with the latest Wayland/Weston clonde and has the Wayland-using versions of Clutter, SDL, GTK, Qt, EFL, FreeGLUT, MPV, GStreamer, and more. Wayland desktop choices include GNOME Shell, Enlightenment, Orbment, Sway, and KDE. The Orbital desktop is temporarily disabled while Hawaii and Papyros Wayland desktops will only work in nested mode.
More details on this fun to try Wayland Live DVD/USB OS can be found via this GitHub page.