Lexus IS 250/220d

It may be a four-seater with a folding hard-top, but the IS 250C isn't gunning for the identically-sized BMW 3-Series convertible, says Lexus. Good thing, some might say. Where the BMW does sporty and sharp-edged, the IS is all about refinement.

The IS, claims Lexus, is the most refined car in its class: less wind noise, more boot space and leg room than the competition, posh shoulder heaters, aircon that adjusts temperature depending on roof position, no sporting pretensions.

Out on the road, under soft blue skies, winding through the snaky passes behind Nice, the IS certainly feels refined. Roof down, front seat passengers are nicely ensconced from the wind, while roof up it's near silent. But jeez, they weren't kidding about the not-sporty bit. With a 202bhp, 2.5-litre V6 driving the wheels through a six-speed auto box - no other engines or transmissions will reach the UK - to call it pedestrian would do pedestrians a disservice. It's a heavy bugger, the IS - in a largely successful bid to limit scuttle shake and chassis flex, the Toyota engineers have packed it with structural reinforcement, making it some 100kg heavier than the saloon at 1,730kg - and it'll unwillingly reach 60mph in nine seconds. The BMW 325i convertible, similarly powered by a 2.5-litre six-pot, manages it in 7.6 seconds. Even in sport mode, the auto' box won't kick down unless you pin your entire bodyweight on the throttle.

But chill out and you'll find there's a nice weight to the steering and brakes and a soft but sophisticated ride. It all fits together in a pleasingly soporific harmony, an insistence that you're going to take things easy. The IS would be right at home on the Californian coast, cruising down a wide, straight boulevard with The Eagles on backing.

In truth, the IS isn't quite as posh as it thinks it is. With its 1980s- digital-watch-style clock and Toyota Auris-borrowed buttons, it suffers from Lexus's strangely piecemeal approach to cabin design: the Audi A5 has a smarter, more coherent interior. And the engine, though smooth and quiet, feels a bit last-century too. Lexus quotes 30mpg on combined economy, though we couldn't top 20mpg in a day of gentle driving. That 325i will return 37.2mpg, and emit far less CO2, too.

And - though these things are subjective - isn't the IS a bit big in the arse and small in the wheels? On the Nice seafront, we passed an Infiniti G37 convertible, the folding hard-top from Nissan's luxury brand, set to arrive in the UK this autumn with a similar price tag and a whole lot more sleekness. It looked great. If your only concern is refinement, the IS 250C does a good job, but its rivals are more capable all-rounders.

Sam Philip