yajl-ruby was the library originally chosen to avoid potential conflicts with Chef. Since Chef requires yajl-ruby, and we use MultiJson, including OJ in the project will then ensure that this instance of Ruby will be using OJ.

While MultiJson aims to provide an abstraction layer for JSON parsers, a few months back I ran into some issues around "pretty formatting". While this isn't a big issue it was enough to scare me into locking to Chef's requirement.

I intend on removing the Chef gem as a dependency from Berkshelf in the very near future so this is probably a moot point if all of the tests are passing.