It is green and clean and completely in tune with modern eco-friendly thinking. Yet the very people who say they want greener cars do not buy it (sales in mainland Europe have fallen far short of Mercedes' great expectations). It is beautifully finished and as finely wrought as a Mercedes four times the cost. Yet it is pilloried for being overpriced.
It is the German giant's second radical small car in a year, of course. First was the A-class, now on sale in the UK. As with the bigger A-class, the Smart has run into stability scares. There has been dark talk of owners losing control on snowy roads in mainland Europe, where the car has been on sale for four months. Clearly, all is not well with the Smart.
Yet it is still the cleverest attempt there has ever been to make a proper city car. Mercedes, initially assisted by Swatch, the watch people, did not wish to launch just another me-too urban runabout - a downsized conventional car, in other words. It wanted to break the mould. Unlike virtually every other car on the road, the Smart car is genuinely original.
How many times do you see the back seats of small cars being used in town? Rightly, Mercedes decided to scrap them altogether. If you need family-sized accommodation, you take the family car. The Smart, on the other hand, is meant for cities. As such, it is very small - more than a foot shorter than a Mini, hitherto the world's smallest production car. Yet it is also very safe in a crash, owing to airbags, a rigid safety cell and anti-lock brakes. It is brilliantly easy to park and to manoeuvre in tight streets.
As the Smart is small, it does not need a large, conventional four-cylinder engine. Three cylinders and 600cc are enough. Just to ensure that it is not left behind with the bicycles when the lights turn green, the rear- mounted engine (under the boot) is turbocharged. Initial acceleration, far from being lethargic, is actually amazingly sprightly. To 30mph from rest, the Smart is brisker than most conventional cars. If you must venture onto the motorways, it can do more than 80mph.
As the Smart is a city car, it has no clutch pedal - because, as every peak-hour-traffic motorist knows, clutches are a pain in the left foot. Instead, the Smart has a sequential six-speed gear change, which is brilliantly simple, allied to an automatic clutch. Also, because it's a city car, and susceptible to urban scars, the Smart has dent-free plastic body panels. These panels can be changed easily. If you fancy a new colour Smart, you can do so simply by changing the car's clothes. The colours are very bright, rather like Swatch watches. (Swatch is no longer a partner in the project, but its original styling philosophy lives on in the Smart.)
The cabin, the very place where owners experience their cars most closely, is superb. It is not swathed in grey plastic of unremitting cheapness and dullness, unlike most other small cars. Instead, it is lively and cheerful and beautifully made. As the designers did not have to cram four seats inside the cabin, the pair of passengers can luxuriate in much space, helped by the big glass area which helps to boost the feeling of airiness.
Around London, the Smart is a cinch to drive, and fun too. The tiny size is the key to its frolicsome nature. Small cars are invariably more fun to drive than big ones, the main reason why the Mini - despite its antiquity - is still such a hoot.
There are three faults with the Smart: the steering requires too much twirling; the ride can be severe on broken roads; and the front tyres, which are very narrow, don't have much purchase on the Tarmac - which is no doubt one reason why Smarts don't like snow. I suspect that the ride may be difficult to fix, but surely the other tow faults can be tackled without too much trouble.
Even with the downsides, I found the Smart enormously enjoyable in London, and very practical. It is aimed at affluent urbanites who will own other cars - so all the griping about its smallness, slowness on motorways, tiny boot, etc, is nonsensical. It is a specialised car, and must be appraised in its specialist domain. And, in the city, there is no finer transport for one or two people.
It may come to Britain at the end of this year, in left-hand-drive form only, although no decision has been taken yet. London, of course, would be the target area. "It is a big-city car, aimed at chic people in chic areas," says a Mercedes spokesman. This story, then, may be a tale of one city. But instead of the gloomy ware served up in the Victorian London that Dickens knew, the Smart is a vibrant, charming, bubbly little thing, that would be as enlivening as it is enlightened.
Make and model: Smart City Coupe. About pounds 7,500. Sales in the UK may start late this year.
Engine: 599cc, turbocharged, three cylinders, 12 valves, 54bhp at 5,250rpm, rear mounted.
Transmission: Six-speed sequential, rear-wheel drive.
Performance: Maximum speed 84mph, 0-60mph in 16.5 seconds, 55mpg.
Citroen Saxo 1.1 X pounds 8,390. Utterly conventional, dull looking, but comfortable and sprightly.
Daewoo Matiz SE pounds 6,320. Stylish but otherwise fairly undistinguished baby car. Good value, though.
Fiat Seicento S pounds 6,495. Current king of the city cars. Although, at the end of the day, it's merely a shrunken version of a normal small hatchback.
Ford Ka pounds 8,020. Cute-looking, cramped in the back, but fun to drive. Under the catwalk body are Fiesta mechanicals.
Skoda Felicia 1.3L pounds 6,999. Gawky styling, but big, roomy and even tolerably well made. A lot of car for the money.