There are no doubts about the benefits for using CTools CBF. Good blog posts are available about it.
Read http://pedroalves-bi.blogspot.co.uk/2012/09/cbf-and-versioning-how-to-develop.html and http://diethardsteiner.blogspot.com.br/2013/10/going-agile-pentaho-community-build.html.
For those ones that need customize Pentaho source code to change or include new features, CBF is the best option.
But, why do I need to compile the entire source code of Pentaho if there is no change in the source code? How to use Pentaho bundled package instead?
To addressing those questions, I’ve made some changes on CBF to use Pentaho bundled package instead of Pentaho source code. Moreover, I’ve also added some new features that I think be important.