If space is the ultimate luxury then the Mercedes-Benz Viano must be among the most decadent vehicles on the planet. Based on the Vito commercial van, it is huge.

The standard Viano has a 3.2metre wheelbase and a 430-litre boot, while the long wheelbase version increases this to a generous 730 litres of luggage space. If that’s still not enough then there is the rather clumsily named extra long wheelbase model with an extra 23cm between the axles giving a massive 970 litres for your luggage.

If numbers like that are hard to visualise, then put it another way: the extra long wheelbase Viano has a boot three times the size of a Ford Galaxy’s. This means that the Viano gets around the problem that affects most other MPVs, namely that buyers must choose between a third row of seats and full use of luggage space.

However, despite its advantages the Viano’s van-like appearance meant that most buyers balked at the hefty price tag when new. At more than £35,000 for a top spec example it is up against stiff competition from vehicles such as prestige 4x4s. Secondhand, however, the Viano begins to make more sense. Used examples start at £16,000 and that means the Viano undoubtedly offers the most Mercedes you will get for your money.

The standard kit list for Viano buyers looks pretty good: all the essentials are there, with entry-level Trend models having electric front windows, air-conditioning and a decent CD player. The higher specification Ambiente model gains an auto gearbox, leather upholstery plus alloy wheels and the addition of air suspension at the rear to keep passengers and luggage on an even keel.

When the range was launched in January 2004 the engine choice was a pair of diesels and a single petrol engine. Of the diesels – a 2 litre CDI producing 109bhp and a 2.2 litre CDI with 150bhp – the bigger engine was better. In a vehicle weighing about 2,800kg the smaller of the diesels never felt comfortable and when laden started to struggle. The petrol engine, a 3.2 litre with 218bhp on tap, endowed this Viano with a decent turn of speed, albeit at the expense of fuel economy. In late 2004 a larger 3.7 litre petrol engine with 231bhp was added to the range, giving an even faster and thirstier option. Nevertheless, the pick of them remained the larger diesel, combining decent fuel economy with enough power for a vehicle of this size.

Most buyers in any case will be considering buying the Viano for one thing only: space. There are three main seating configurations. Two three-person bench seats in the back (giving a total occupancy of eight); one bench seat and two individual back seats; or two rows of two seats in the back. In the latter positions the first row of seats can be turned around to create a four person conference set-up with rear passengers enjoying face-to-face seating.

Seat backs can be folded, creating useful table tops, or a larger work table can be created for passengers to picnic on as the miles zoom by. Whatever seating configuration you choose, the Viano provides a smooth ride, so much so that you could believe you were travelling by rail rather than road.

For the driver and front passenger the Viano is equally spacious and although the dashboard looks a little like a commercial vehicle’s compared with an equivalently priced Mercedes-Benz saloon it is still a big improvement over its forerunner, the V-class.

It is also a better vehicle to drive than many may expect. The rear-wheel drive is unusual among super-size MPVs and the vehicle’s relatively tight turning circle makes it surprisingly nimble in town. At higher speeds the interior is well insulated against road and wind noise, although the Viano’s 1.87m height and 1.9m width could hardly be called streamlined.

The Viano will never win any beauty prizes but in terms of moving lots of people and heaps of luggage over long distances it is one big step in the right direction.

Gearstick Dash-mounted stick falls naturally to hand but most buyers still prefer the ease of the automatic gearbox, which is standard on all petrol models

Storage Underseat trays, large glove box and door bins provide plenty of extra storage space

Tyres Rear-wheel drive helps reduce front tyre wear but check for incorrect inflation, which can shorten life expectancy

Doors Sliding side doors make rear access easy

Upholstery Leather upholstery does its best to transform the interior into a much more upmarket environment but check for wear on driver’s seat

Servicing Variable service interval allows Viano to travel 18,000 miles between visits

Safety Twin airbags, brake assist and traction control are standard

High mileage Favoured by chauffeur companies as the ultimate people carrier, so check registration document for signs of company ownership

Vital statistics

Model Mercedes-Benz Viano 2.2 CDI

Engine 2148cc, four cylinders

Power 150bhp

Transmission Five-speed automatic

Fuel 32.1mpg (combined)

Acceleration 0-62mph: 13sec

Top speed 111mph

Values

Mileage 10,000 20,000 40,000

2004 04 Trade £17,300 £16,450 £15,050

Retail £20,750 £19,995 £18,595

2005 05 Trade £19,100 £18,200 £16,600

Retail £22,750 £22,000 £20,250

2006 06 Trade £21,050 £19,950 £18,250

Retail £24,750 £23,750 £22,000

The one to buy

Mercedes-Benz Viano 2.2 CDI Ambiente 2004 04 with 40,000 miles. Pay £18,595 at a dealer or £17,000 privately

Or for similar money

2003 53 Volvo XC90 2.4 D5

2004 04 VW Caravelle 2.5 TDI

2005 54 Chrysler Grand Voyager 2.8 CRD

2006 55 Renault Grand Espace 3.0 dCi

2006 56 Mitsubishi Grandis 2.0 DID Warrior