It really isn't, which is sad, because it's like 95% Awesome and 5% Showstopper Bugs. Here's the most damning aspect of it: if you sign your ClickOnce application (which you are required to or else ClickOnce's installer displays scary "Don't Install This" messages), then the cert expires,
every user has to uninstall and reinstall
. Completely untenable.
http://github.com/github/shimmer is our plan for the future.