A while back I started a crapstorm on the qa list about maintaining META.yml which led to a Module::Build vs. ExtUtils::MakeMaker debate and a rant by Schwern.
For me at least, M::B just has better support for maintaining the various information in META.yml moreso than in E::MM. My beef with using the 'traditional' option is that it puts optional modules into the Makefile PREREQ_PM making them build requirements (as apposed to just requirement for test running).
Which leads to the whole debate of if a passing 'make test' is a requirement of a 'successful build', then why aren't the tests just run at the end of 'make' or 'Build'.
But I digress...