But before getting too excited, Weston 2.0 doesn't represent some break-through changes but rather was bumped away from the Wayland versioning rhythm due to its new output configuration API breaking Weston's ABI. Thus the major version bump.
Weston 2.0 has queued a big set of changes including a new output handling API, DRM compositor improvements, support for using EGL_KHR_swap_buffers_with_damage, initial window positioning for XWayland apps, desktop shell refinements, and an assortment of other fixes and improvements. This is interesting for those experimenting with Wayland or developers looking to test Wayland's new capabilities, but for end-users running KDE, GNOME, or Enlightenment, their own compositor work is happening in parallel.
The brief Weston 2.0 release announcement by Samsung's Bryce Harrington can be read on the Wayland devel list.