We like
Diesel refinement and low-speed torque, fuel economy, interior comfort and space, build quality

Room for improvement
Susceptible to cross-winds, largish turning circle, expensive options

Okay, more automotive confessions. We’ve got a soft-spot for the diminutive wee Mercs.

Yes we know: the A-class looks like a noddy car to some and its dynamics and steering may not be super-sharp.

But for today’s congested cities, its compact dimensions make it ideal for city driving.

Then there are the safety levels – ESP in a small car for goodness sake - and a spacious cabin with rear seats (optional) you can rip out to create a van.

Such features, and the badge madge, help redress any fears of driving what is essentially Merc’s "budget" hatch.

Then, just when we's got used to the A-class, along comes the B-class, which effectively takes over where the long-wheelbase A-class left off.

It’s bread-van looks, longer snout and huge glass area promised an equally commodious cabin but isn’t that what the A-class was supposed to have?

In many areas, the B-class offers similar characteristics to its smaller sibling.

It has a high, upright seating position, versatile cabin, sound ergonomics and is a reasonably nimble handler - but it also adds a longer wheelbase for an improved ride.

Mercedes-Benz tells us that buyers are also attracted to the B-class because it has a more conventional bonnet, where the A-class front virtually disappears into the windscreen without any clear delineation. For us, that’s part of the A-class appeal: its cute looks.

Our confusion over the Mercedes alphabet soup of models has been compounded with the arrival of the B-class.

Then we drove the B180 CDI, which goes a long way to clarifying what this car is really about in the overall scheme of things.

Adding a diesel into the B-class mix makes a lot of sense. What could be described as a competent car in petrol form suddenly becomes even more desirable purely by opting for the diesel.

The B180 CDI gets the latest-generation common-rail engine that is EuroIV emissions-compliant, has a sophisticated injection unit that ensures quieter operation, and 79 per cent of its available torque comes in from just 1300rpm, giving particularly strong low-speed acceleration.

Although available in a six-speed manual, the diesel seems particularly well suited to the continuously variable Autotronic transmission in the car we tested, the rise and fall of the rev-counter virtually the only indication that the engine was doing any work.

The CVT has both a comfort and sport setting to change the shift pattern, as well as a pseudo-manual mode.

It pulled strongly up inclines and mid-range overtaking manoeuvres were quick and without fuss.

Mercedes quotes a zero to 100km/h time of 11.3 seconds, which does not seem startling by class standards but the diesel gives the impression of being a lot quicker than the stopwatch suggests.

As you would expect of a turbo-diesel, fuel economy is a strong point. The B180 CDI delivers 5.6L/100km in combined driving conditions and is able to cover more than 960km on one 54-litre tank.

It shares the suspension system of its petrol siblings and the A-class. That means strut front gear with a parabolic rear axle laterally located by a Watts link, all designed to contribute to the car’s stable on-road handling and reasonably plush ride.

The diesel also gains an improved ESP system that adds has steer control, which provides servo assistance in critical situations to help the driver stabilise the car.

Over some muddy gravel roads we managed to activate the ESP several times, stabilising the car mid-corner. Unlike some Japanese systems, which intervene too early, the ESP in the B-class is progressive and allows a reasonable window of opportunity to correct a skid before being activated.

Apart from the fail-safe ESP, there is also a selective damping system that sharpens shock absorber responses depending on the driving situation.

On bitumen, the B180 CDI rides in a composed, well-controlled manner. There is the characteristic, and predictable, understeer when pushed and the electro-mechanical power steering is a little too light for our liking.

Despite having a longer wheelbase than the A-class, rough corrugations still upset the B-class as the suspension fights for rebound control. The car is at its best on smooth bitumen.

The B-class’s selective damping system, while a welcome addition, seems a little redundant in what many will see as a prestige-luxury car. Enthusiasts would look elsewhere for pure dynamic performance.

At 4720mm long, the B-class is 5mm longer than a Holden Astra wagon, meaning it offers a seriously large cabin with a multitude of options for the rear luggage area, including the Vario seating system that allows the rear seats and front passenger seat to be removed.

Standard equipment includes six airbags, ABS, traction and stability control, brushed aluminium highlights, cruise control, tyre-pressure sensors, rain-sensing windscreen wipers, a trip computer, six-speaker CD stereo, air-conditioning, a multi-function steering wheel and a full-size spare wheel.

The B-class is built using the same principle of the A-class – a sandwich construction method that lifts occupants about 200mm above conventional hatches, with the engine inclined up front so it deforms under the car in a frontal collision.

B-class has all the elements you would expect of a Mercedes. A diesel option now gives it a desirability factor that is a simple as A, B, C.