It took four years and more than 2bn euros, but the new Mercedes-Benz E-Class is finally out in the open and ready to continue the Merc's work of being the most successful luxury saloon in the world.

The outgoing car averaged more than 200,000 units sold a year, and around a quarter of all new car buyers in this segment have plumped for the E-Class, helping achieve a total sales of some 1.4 million cars.

The styling of the model, with its very individual dual front lights treatment, has more than anything else set it apart since the current car was premiered in 1995.

They've not interfered too much with a good thing here. The light lenses are a more 'teardrop' shape to improve the aerodynamic look. Changes to the radiator grille and the front apron add a perception of extra width ... and in fact the car IS wider, and higher than the older model.

There's more curviness about the front, the bonnet and the roofline too, making the car look more compact, almost coupe. The best view is from low down a little ahead of the front three-quarter.

At the other end there's now a fairly short rear deck, produced by a very long backward 'reach' of the rear window, while the new back lights wrap strongly around onto the rear side panels. The third brake light is set discreetly into the top of the boot-panel. All in all, a very tidy effect.

It is more than just good looks though - the new car has one of the best drag coefficients of any in its size and class. At Cd 0.26 it is a significant improvement on the current vehicle, itself no mean achiever in the aerodynamics stakes.

The inside of the car is designed around what the standard '95-percentile man' of 2005 and the '5-percentile woman' of 2005 are expected to be. These represent the upper and lower limits of human size, and in this instance are significantly greater than today's versions. Increasing human height in developed nations has ramifications for seat size and positioning, leg and elbow room, and, of course, headroom. The new E-Class addresses all these.

We're carrying more stuff too, and a 20-litre increase in boot capacity attends to this matter, partly accomplished by shifting the fuel tank from above the rear axle to under the rear seat. There's no spare wheel, just a tyre sealant kit, and the extra space under the boot floor is now for carrying hideables.

And for the first time, the E-Class now has folding rear seats, acknowledging the fact that even M-B drivers need to carry awkward flatpacks home from the local Woodies at times.

The dashboard design features a fine trim of wood, and the surface plastic is soft to the touch thanks to a polyurethane plastic coating backed by foam. It has a leather-look finish.

There's a fair bit of chrome detailing in the front area to brighten things. The instruments consist of three main dials for speed, revs and analogue clock (still prefer those, I do). A display in the middle of the speedometer offers text warnings of malfunctions.

On the innovative gizmo track, we'll find a button which raises up the switch panel on the dashboard, allowing access to the tape deck or optional CD changer behind it and a stowage compartment.

You can have keyless entry as an option. There is a solar-powered ventilation blower which keeps the car cool automatically after you leave it, without needing to use the car's electric system. And an optional version of the climate control allows four occupants to individually tailor their heat/cool preferences.

And if you're the owner of an E-Class with the multicontour seat option that allows individual adjustment of the seat and seatback contours, well, you can have it again as an option in the new car. For those who fancy a fanned bottom, the leather-seated version can come with five minifans under the seats to circulate cool air.

The new E-Class will also offer the option of the 'intelligent' cruise control currently available in the S-Class. It uses a radar system to monitor what's happening 150 metres ahead of the car, and adjusts the cruise speed to match that of any vehicle in front.

A quick look at the engine options: the very top-end version will have the 306hp V8 5-litre from the S-Class, though we're unlikely to see many of these in Ireland. At the other end of the petrol scale will be the 2.6-litre and the 3.2-litre V6s, while there will be two 4-cylinder diesels with 2.2- and 2.7 litres capacity. The petrol engines are more fuel efficient than they were before, and the diesels have increased power outputs.

There's no mention of an E200 petrol, but if they want an entry-level price here in Ireland, I guess we'll see one.

All manual transmissions in the smallest petrol and the two diesel engines are 6-speed, and an optional SEQUENTRONIC eliminates the need for a clutch pedal and also provides a fully-automatic capability. There are, of course, fully-automatic transmissions in the E320 and E500 versions.

The makers have added a couple of safety/chassis innovations. For instance, the new car is the first volume model to feature M-B's Sensotronic Brake Control, which uses electronic rather than hydraulic or mechanical means to transmit braking commands.

The AIRMATIC DC air suspension system used on the S-Class since 1998 is also now an option on the E-Class, controlling both springing and damping functions using microelectronics.

This introduction has only touched on some of the technology. But what's more likely to be the biggest selling point for the new E-Class is the success of the old. Because, when you get right down to it at this level you just can't beat satisfied customers.