And another build system joins the fray!

Two things that stand out is the focus on reproducible builds (which also necessitates versioning your build system and building everything from source) and that it foregoes the use of an external dependency resolution tool (like make or ninja). The Python like declaration syntax looks interesting too.

I do wonder how this would fly at work - I know our Release Engineering team would probably gag at the idea of not integrating with our system compiler and libraries, but certainly could be interesting for stand-alone client builds.

Nope nothing for work ... Bazel actually thinks that u have a clue about dep mgmt...which I dont really See in our system ... Think about building Maven or Ant from source...a good excercise for future RelEng hirings...hadoop is also a nice try