I traded a C300 for an R350 because of an expanding family. The vehicle has not disappointed on bit. I fit my family of four with ease and without baggage, this vehicle will fit 6 people comfortably. The car lacks a little power but is not noticeable once one the highway. No problems so far with as I've read in some reviews. The vehicle has striking presence and luxury is apparent as you roll down the street. I would definitely keep the R-350 for a long time as comfort is not comparable for this price range.
Fun vehicle to drive with your family, specially for long trips...
The fuel economy is not prime but it is a pretty heavy vehicle.