Wow, i wouldn't have thought that. Since i moved away from Ubuntu to Debian mostly because all this upstart, mir, advertising solo attempts, it's nice to hear that.
Now i'm waiting for the same blog post about supporting Wayland and i may even switch back sometimes.
AFAIK, Packages are available in Arch and the latest releases of Fedora may have Wayland packages available, but it's not (yet) the default window system for either distro. Fedora has been planning to ship Wayland in the main distro for some time, but it's not an easy task, and it keeps getting pushed out to "the next release". They want to do things right, and seem to be the biggest supporter of Wayland, so it may still be some time before a major distro starts using it as their primary GUI layer (aka windowing system, though I'm not so sure that's an accurate term for these things anymore)
In addition, GNOME is busily porting everything to work on Wayland. I think when that is finally done, we will begin to actually get Wayland-by-default on a few dists, and from there, well... that depends on how well it works!
I personally have nothing against either Wayland or Mir, I just want my system to work and if I can get better security, performance, features, etc out of it... score!
Indeed, I think we're about to see some very interesting times in the next year or so, with regard to GUI/Windowing systems in the Linux world.
Wayland has been a long time coming, and I do hope that's because those working on it are really shooting to get things right. Mir is interesting, and it looks like it will be able to do some things that Wayland/Weston can't, or would require some difficult hacks or even spec changes to make work. I don't know if Mir would be better than Wayland for me, but if you ignore all the FUD from both sides, I think the bottom line is that Mir is better for Canonical's plans unless or until Wayland/Weston can be changed to accommodate their needs.
I personally have no positive or negative opinion on Mir vs. Wayland, but I hope that at least one truly delivers on their potential and shows a clear improvement over our old trusty ;) X11/Xorg.
Wayland is used in the Sailfish OS shipped on Jolla phones. It also seem to have traction on Raspberry Pi, mostly because X really sucks on their low-powered hardware.
Gnome is likely to be the first DE to run on wayland. Gnome 3.12 is being delayed to release lockstep with wayland - especially to support some of the gnome-settings-daemon stuff.
Now i'm waiting for the same blog post about supporting Wayland and i may even switch back sometimes.