title: Ruby on Rails: What are Erubis' disadvantages and why isn't it packaged with Rails by default? How to set it up?
body: <p>I just discovered Erubis, a replacement for the default view renderer for Ruby on Rails. However, from what I can tell from reading about it, it's superior across the board.</p>
  
  <p>It is much faster.<br>
  It has many more options.<br>
  It can prevent cross site scripting without having to use h.</p>
  
  <p>Does this have any disadvantages versus the standard erb renderer? Why isn't this the standard renderer packaged with Rails?</p>
  
  <p>Also, the docs for Erubis say to install it just by installing the gem, and then add the following to environment.rb:</p>
  
  <pre><code>require 'erubis/helpers/rails_helper'
  #Erubis::Helpers::RailsHelper.engine_class = Erubis::Eruby # or Erubis::FastEruby
  </code></pre>
  
  <p>Reading the docs, FastEruby seems to be just a faster renderer than Eruby. Why wouldn't it be default and used by everyone?</p>
  
  <p>I'm highly interested in using the engine erubis::EscapedEruby which automatically calls h to escape html on fields from the database. Are there any gotchas I should be aware of or does this pretty much solve  all cross site scripting?</p>