In July 2002, having waited six months for the new Mercedes- Benz E-class to hit the showrooms, I borrowed one. After driving several hundred miles I was left with one overwhelming emotion: disappointment.

I loved the sleek lines and the clever technology; the huge boot swallowed the largest load. But none of this could hide the car’s Achilles heel: its engine. The 177bhp V6 petrol engine fitted to the E240 sounded harsh when pushed, performance felt moderate and after 800 miles it had averaged only 21mpg.

But my reaction was out of step; almost universally the car was heaped with praise. And it was 18 months before my opinion was to change.

This time I drove an E270 diesel. It was blessed with virtually identical power to the petrol car on paper but in reality the leap in torque produced a smooth wall of power that made the car genuinely fun to drive, and it also averaged close to 40mpg. At last I understood what everyone had been saying: this was quite possibly the best executive car money could buy.

I also tried the more modestly priced E220 diesel with 150bhp. It still felt good, and the 3.2 litre E320 diesel with 204bhp was a real hoot. With these cars Mercedes proved that not only had diesel engine technology caught up with the petrol equivalents but actually eclipsed them.

In fact only one petrol version is comparable with the diesel. The E500 boasts a 5 litre V8 that kicks out 306bhp and while economy is not its forte you get huge performance — 0-62mph in 5.8sec and a top speed limited at 155mph. A used example will cost about £25,000 and makes an excellent buy. Both the E200 and E320 petrol engines, boasting 163bhp and 224bhp respectively and introduced in 2003, are best avoided.

Once you’ve chosen your engine you have to decide on the trim level. The entry-level Classic is far from basic with climate control, alloys, leather steering wheel, electric windows and auto dimming rear mirror as standard. It has front, side and head airbags, antilock brakes and traction control. The car scored five stars in the Euro NCAP crash tests.

Commanding a premium of about £1,500 on a used example is the Elegance model which adds walnut wood veneer, automatic rain-sensing wipers, power headlamp washers and electrically folding door mirrors. For about £750 more the used Avantgarde adds flashier alloy wheels, sports suspension, bi-xenon lights, blue tinted glass and a dark wood interior.

Whichever you plump for it’s best to choose an automatic box. They fetch a premium of about £1,250 over the six-speed manuals but you’ll enjoy near-identical performance, equivalent economy and easier resale.

On the move the car feels smooth, quiet and well planted on the road, the clever electronics intervening when the car reaches its limit. Leather upholstery and sat nav are desirable options and add about £500 apiece to used values, but multicontour seats that massage your back and Airmatic suspension do little to enhance value.

Whichever E-class you choose it’s a pretty safe bet that you will be buying a great car. Just make sure it’s diesel.

Satellite navigation A desirable option that adds around £500 to the value of a used car

Front arm rest Air-conditioned to keep your drinks chilled

Transmission Six-speed manual best avoided as auto suits the car best. You will find a range of five, six and seven-speed derivatives across the models

Climate control Standard on all models with some cars having an optional upgrade for separate climate control to the rear

Insurance Relatively modest group 13 insurance on the E270 diesel

Service history Avoid incomplete history on a car that is going to set you back £20,000 plus

Sunroof Optional panoramic glass sunroof fitted with solar panel that powers a fan to circulate air and keep the car cool when stationary. At £1,250 it is a rare option and adds little to used values

Upholstery Cloth is standard with Avantgarde models having a cloth/leather combination. But cars with leather are common and fetch about £500 more

Bodywork Aluminium used extensively in construction of bonnet, front wings, rear parcel shelf and boot lid, which reduces the car's weight

Alloys Standard on all models. Avantgarde gets the chunky five-hole design

Tyres Check the inside edge for uneven wear on the front wheels

Vital statistics

Model Mercedes-Benz E270 CDI saloon
Engine 2685cc 5-cylinder 20V DOHC
Power 177bhp
Transmission Five-speed automatic gearbox
Fuel 39.2 mpg (combined)
Acceleration 0-62: 9sec
Top speed 138mph

The one to buy

Mercedes-Benz E270 CDi Avantgarde auto saloon 2002 02 with 30,000 miles. Pay £23,500 from a main dealer or £21,500 privately

Or for similar money...

2004 04 Jaguar S-type 2.7 V6 diesel Sport

2004 54-reg Lexus GS 4.3 SE auto

2003 53-reg BMW 530d SE manual

2002 02 Audi A8 S8 saloon

Values: Mercedes E270 CDI Avantgarde auto



Source: estimates based on confidential CAP black book prices. ‘Trade’ is what a dealer would pay to buy your car; ‘retail’ is what you pay a dealer. Six-speed manual models are about £1,250 less than autos