Is it worth adding in some guidance around where to use it? For a hash where you can use only symbols as keys (option hashes in methods and creating instances for tests with factories being the obvious places) use the new style. If you could add other keys in there, stick with the old style. It seems the only reason to not use the new style is because changing from new to old style when you add a non symbol key is a pain (not to mention an annoying diff for the reviewer).