Why emacs?
Previously I was developing with dynamic language, like js, ruby, python, via using vim. Vim is a great editing tools with different internal mode(command/visial/insert mode). But the original reason why I intended to migrate from vim to emacs is the powerful REPL environment as well as other embedded function.
Trouble from vim to emacs
I was starting to read the documentation of emacs, and acquainted with new key-binding. Then I realized editing in emacs is less effective than in vim. Thus I came up to evil, an extensible vi layer for Emacs. Combing emacs with evil will maximize the productivies, therefore it is not necessary for you to remember all the key-binding under emacs environment.