Can you share some details about what it's like to drive using the s550 system?
I have the older 2011 system which is distronic plus with stop and go. Basically you never need to touch the gas or brake on the highway, even in rush hour. The only 2 things that fool the system are traffic lights. It can not stop there on its own. And if a Car is at a full stop and your coming up at 60mph etc behind it. You need to brake. If that car is moving at say 20 mph, the distronic plus will brake and also alert you to "super brake" if you get too close. "super brake" is where the brakes are pumped and you just tap them for full braking power. This is part of front collision assist.
The 2014 S550 now steers. I don't have that. but there are many youtube videos of it.