I'm just facing the same issue of deciding which framework to use for our own build files. BuildMagic looks very promising since it handles many configuration issues needed by the specific build file of a project.
I also came across "Krysalis Centipede" http://www.krysalis.org/centipede/ which also looks very promising.
I also could not find any documentation on BuildMagic, which is very needed in order to figure out all the details up, especially the recommended settings in a project using BuildMagic.
Any help will be appreciated,