No experience with this particular model year but I have always loved the S8. Most recently, I had some track experience with a 2012 S8 and was blown away that a big sedan with 4 grown passengers in it could do what it was doing on a race track.
My general opinion is that those who have a S Class want to RIDE in a luxurious and prestigious car. Those who have a S8 want to DRIVE a luxurious and sporty car.