title: String vs. StringBuilder
body: <p>I understand the difference between <code>String</code> and <code>StringBuilder</code> (<code>StringBuilder</code> being mutable) but is there a large performance difference between the two? </p>
  
  <p>The program I’m working on has a lot of case driven string appends (500+). Is using <code>StringBuilder</code> a better choice?</p>