I gave a presentation last month at Drupal 414 on building responsive websites using the Omega framework, and compared apples to oranges with version 3 and 4.
We've all been there - create this awesome responsive design for a client's website and then you have to try and slap a Facebook Like Box in there..somehow..without breaking your responsive work. Sucks, doesn't it? But it doesn't have to. Using a little jQuery you can cause the Facebook Like Box to re-render on window load or resize allowing it to become responsive versus hardcoded.