I have been to the Residenz many times as I used to live in Wurzburg and I visit whenever I am back in Germany. I took my family there a few weeks ago for the first time and they loved it. The staircase is an amazing piece of art and is always my main reason for visiting. It's beautiful and well worth the visit. I forgot to go into the chapel accessed from the side of the palace. Don't forget if you visit because it is also very impressive.