Lush usually describes thick green vegetation, Fantasy Suites at the Palms Casino, or people who drink too much alcohol, but it’s the word that comes to mind when considering the powertrain in the Mercedes-Benz S-Class. It’s vivid, it’s luxuriant, it’s smoother than Glenlivet. Quiet, fluid power flows from the 5.5-liter V8, the automatic transmission shifting flawlessly between its seven forward gears. Throttle tip-in is soft, perfect when chauffeuring heads of state or sleeping children, but the Benz rises to any occasion with a heavy dip into the throttle. Mercedes says that the S550 will get from rest to 60 mph in just 5.4 seconds.