Facebook Buck http://github.com/facebook/buck build is fast. In some cases, it is faster than LayoutCast due to its multi-process build. The biggest problem with Buck is, it requires you to change a lot of codes, and restructs your project in small modules. Indeed, it is troublesome to just make it work properly on the existing android project, especially if you have big project. I have tried using Buck build system instead of Gradle on my test project. However, it took me a week just to make it work.
What I needs is a build tool that is easy to setup, fast as Buck, and provide a Run button in AndroidStudio. So I created LayoutCast.
LayoutCast is a little tool to help with that, it will cast every changes in your Java source code or resources (including library project) to your phone or emulator within 5 sec, and does not restart your application.