Audi's new A3 Sportback has that winning 'want one' factor and is a fine choice, says Matt Joy,PA motoring editor.

Audi made a big impact in this sector with the original A3, which started life as a three-door only model but the added practicality of the Sportback version pushed it out to a wider audience.

Over each generation it has raised the stakes in terms of cabin quality and driving dynamics to continue to set the benchmark. Now we're on the third iteration, and with the three-door version a remarkably well-rounded, capable car, the Sportback promises much having been named What Car? Car of the Year 2013.

The extra pair of doors are well integrated into the overall shape. The A3 is the perfect example of how Audi manages to evolve a design, keeping a clear visual link to the previous model but introducing some fresh elements. The narrower nose looks more purposeful, the headlights have a more edgy appearance, in particular the strong lines produced by the LED elements. The roof curves neatly into the rear, marked out by chrome roof rails and the way the tailgate slopes steeply away makes the Sportback almost look like a mini-estate; certainly no bad thing. Like most modern cars it looks best on larger alloy wheel options, and it wears both sober metallics and more vibrant shades – even white – very well.

The extra pair of doors makes getting in and out of the back easier so the A3 Sportback is a genuinely viable family car. You might hesitate to let sticky-fingered little ones aboard, given how plush the cabin is, but they certainly won't grumble. Big kids have proper head and legroom too, and the third rear window rather than a thick pillar helps more light into the back of the cabin too. And its practical nature continues with 380 litres of boot space with the back seats in place and 1,220 litres with the seats folded.

All this is pretty much as you would expect, but once behind the wheel you really see where progress has been made. The A3 is the first Audi to use the architecture that will underpin other Audis and compact Volkswagen Group cars so lots of money has gone into developing this crucial element of the car – and they have to get it right.

The A3 Sportback is initially offered with 122PS 1.4 and 180PS 1.8 TFSI turbo petrol and 150PS 2.0 TDI turbo diesel engines. They will be joined by 105PS 1.6 and 184PS 2.0 TDIs and 105PS 1.2 and 140PS 1.4 TFSI, the latter with cylinder-on-demand technology which shuts down two cylinders at low to intermediate loads and while coasting. There will also be quattro all-wheel drive versions.

The first thing you notice is that the A3 is remarkably quiet on the move. The diesel engines are hushed but you get the best experience in the petrol models, which at rest are virtually silent (even when the stop-start system hasn't yet kicked in) and you rarely hear anything more than a controlled hum as it moves along. That goes a long way to making the Sportback a very comfortable car to spend time in.

The other significant element is the ride quality. Even sportier S line models, which have sports suspension and big alloy wheels, feel superbly controlled and comfortable, riding bumps without divorcing you from them altogether. Whether simply cruising or having a bit of fun on a challenging road, it is extremely capable and feels like a car from the class above.

That also goes for the cabin, which moves the game on yet again. There are numerous options and various trim combinations but it almost feels like you're sat in a luxury car rather than something merely premium. The revised multimedia interface (MMI) system takes up less space and is a cinch to use without taking your eyes off the road, while the big colour screen is crisp and clear without being intrusive.

Maybe you thought Audis were attractive and a bit flash, but not the kind of car bought by sensible people like you. Well consider yourself told otherwise – the A3 Sportback is practical, comfortable and efficient, yet still delivers plenty of luxury and the 'want factor' that you might feel a bit guilty about. No need – you can buy one, know you've made a fine choice and be smug about it all at the same time.