title: Difference between presentModalViewController and presentViewController?
body: <p>In iOS 5 SDK, there're two methods of UIViewController, presentModalViewController:animated: and presentViewController:animated:completion:. </p>
  
  <p>What's the difference between these two method?</p>
  
  <p>The documentation says: The presentViewController:animated:completion: method is the preferred way to present a modal view as of iOS 5.0. </p>
  
  <p>If I use a presentModalViewController:animated in iOS 5, will it causes a bug?</p>
  
  <p>Are they functionally-same?</p>