What is it like to drive?
If more car manufacturers fitted engines like the one in the B200d, diesel propulsion wouldn't be a pariah. It's certified in real driving tests as extremely clean for toxic soot and NOx emissions. It's also economical for urban and gentle rural driving, and torquey, which is why Mercedes continues to believe in the fuel.
And from behind the wheel?
It's extremely smooth and quiet – at least for an engine without spark plugs. The smooth and quick-witted eight-speed transmission helps a lot. But it's not that powerful, and struggles with some overtakes even when empty: imagine it loaded up with five people and luggage.
What’s the petrol like?
The B200 petrol sounds a bit thrashy and uncouth at least in the middle revs, but at least it's quiet, and when you ask it to give its all, it doesn't get any worse.
The suspension is well-judged for the job: carrying people. It's absorbent in town and placid and quiet over lumpy roads at country speed. Harshness and tyre noise don't bother you.
Passengers will be glad (unless they're late for something) that the driver is given no incentive at all to press on when the road's twisty. There's understeer and float to contend with. The steering is well-weighted and geared, but it's numb and rubbery to small inputs.
Does the tech get involved?
Of course. The cruise system doesn't only hold you in lane and keep station behind the car in front, but if there's no-one in front it will still slow down for upcoming roundabouts and bends, and speed up afterward. Its blind-spot system now detects cyclists.
The standard collision prevention system is sophisticated in theory. But its calibration is pretty nervous for narrow British roads. It frequently yanks at your trajectory, or even brakes, when you're just driving along a curving road and it sees oncoming traffic you know to be harmless. Others are catching up with Mercedes' assistance systems.