With fantastic looks, amazing comfort and plenty of equipment, the new E-Class is another great four-seater cabriolet from Mercedes. The big V8 engine sounds terrific, and you'll never be left wanting more power. While rivals offer a sharper driving experience, the E500 excels in transporting four people at speed in refinement and luxury. However, this comes at a price potential owners will need deep pockets not only to buy it, but also to run it

Meet the mightiest E-Class drop-top yet! We gave the entry 2.2-litre diesel model full marks, but can this range-topping E500 5.5-litre V8 petrol variant continue the fantastic run of form?

Packing the only powerplant that¹s been carried over from the previous E-Class range, and the only engine in the line-up not fitted with BlueEFFICIENCY eco technology, the E500 is not cheap to run it returns a meagre 25.7mpg.

Worse still, under the Government¹s latest road tax rules, cars classed as highpolluters which the E500 is deemed to be, as it emits 257g/km of CO2 are hit with an inflated bill in their first year of registration.

That means E500 owners will have to pay £950 in 2010, with that figure dropping to the standard rate of £435 in 2011. But does the Mercedes' performance make up for the extra cash you'll have to hand over to the Treasury?

Certainly. Top speed is limited to 155mph and 0-62mph takes only 5.3seconds! The E500 rockets off the line with a lovely bassy growl from the exhausts. And it only gets better when you lower the roof.

In addition, its seven-speed semi-automatic gearbox is smooth and shifts are quick. It's so good that we rarely needed to use the steering wheel-mounted paddles to change gear manually.

Thanks to Mercedes' new Aircap system, the E-Class boasts reduced wind and noise in the cabin when the roof is down. A motorised airfoil sits on top of the windscreen and can be raised or lowered at the touch of the button. Working in conjunction with a clever climate control system, the E-Class Cabrio was comfortable even in temperatures as low as the eight degrees celsius we experienced on our test.

When we did eventually put the insulated 'acoustic' fabric roof up, it tookonly 20 seconds to slot in to place and givesthe Cabrio an impressively cosy and quiet feel.

In corners, the E500 is composed, and its accurate steering gives it a sporty feel. However, it's not as sharp as some of its rivals, even with the standard Sport package. Optional on all other models, it includes sharper throttle response and active damping.

Where the E500 does score is comfort the ride is beautifully soft and the seats are shapely. Unsurprisingly, given its running costs and price tag, Mercedes expects only two per cent of buyers to opt for the E500. But what they'll get is a charismatic and desirable express.