What is it? This is the latest version of BMWs class-leading compact executive an all-new car that, the company says, shares nothing with its predecessor.
Its larger and more spacious than the model it replaces, yet most models are lighter than their predecessors, as well as quicker and more efficient.
The range starts with the 316d ES, but so far we've only driven the 328i and the 320d in Sport and Modern trims respectively, and with the optional eight-speed automatic gearbox rather than the standard six-speed manual.
Visually, the new car stands out from the previous version with its lower, sportier nose, while a variety of new trims and options allows owners more opportunity to personalise their car than in earlier models.
Whats it like to drive? Theres no doubt this car has a tough act to follow: the outgoing 3 Series is still the best car to drive in its class, even as its about to go off sale.
The good news is that the new car is the perfect replacement, because it tries to remedy some of the outgoing cars few shortcomings, without losing what made it so great.
Given that the most common complaint about the previous car was its firm ride, its no surprise that the phrase you hear most often bandied around by happy BMW engineers is more compliant. To cut a long story short, the new 3 Series does have a more comfortable ride, albeit still with a slightly firm feel at low speeds.
By the same token, just as important is what the new car hasnt lost its superb handling. It uses its rear-drive chassis and excellent weight distribution to give an extremely well balanced drive.
As part of our test drive, we were let loose on the Circuit de Catalunya racetrack, and even in the pouring rain that accompanied our session, the car was wonderfully well balanced. It turned into corners keenly, the nose gently running wide if you went too fast but coming back into line when you came off the power. Then, as you eased back on, you could feel the rear end lightening up as the driven wheels started to lose grip.
The result is a perfectly balanced car that's a joy to drive and all done, of course, with the back-up of effective electronic safety systems.
On the road, all those same traits were displayed, and we have no doubt that this new 3 Series is the best car in its class to drive.
In any situation, it felt in its element: easy to guide through city streets, a joy on twisty country roads and solid on the motorway.
Both the petrol-powered 328i and the 320d diesel have fine engines, too. With more than 240bhp, the 328i dispatches the 0-60 sprint in less than six seconds and responds keenly right across the rev range.
Even so, for us the 320d is the better of the two and not just because its about 1000 cheaper. It has more torque than the 328i, so responds even more keenly, as well as averaging almost 63mpg and emitting just 119g/km of CO2.
We drove both engines with the optional eight-speed automatic gearbox, and it worked well. In automatic mode, it slurred neatly between the closely stacked ratios, while the paddles behind the wheel also gave a decent manual shift.
Whats it like inside? Evolution is the watchword inside the new 3 Series. Yes, that means it doesnt look markedly different to the old one, but its still a decent cabin, with the controls and console neatly angled towards the driver.
Dominating the top of the centre console is a 6.5-inch screen, which displays information about the cars status, as well as (where fitted) the sat-nav, all of which is controlled by the fine iDrive system that will be standard across the range.
Fit and finish were excellent, as were (for the most part) the materials used. Our only reservations centre on the odd contoured wood used in the Modern-trim car and the fact that there are rather a lot of similar-looking buttons on the centre console.
Otherwise, theres little complain about up front. The driver has plenty of room, as well as a wide range of adjustment on both the seat and wheel, and a decent view out.
The real improvement is in the back, where you can fit a couple of six-footers. During our test we were able to complete a long journey with four adult passengers on board something that would have been impossible in the old car. True, a Ford Mondeo is a better and more spacious family car, but for the first time a 3 Series is a genuine proposition for a family.
It even has a decent boot, with split/fold seats available although the saloon body limits its ultimate versatility.
Should I buy one? It shows just how dominant the current 3 Series is that the only car the new model has to beat is its predecessor and that it does. In short, if youre in the market for a compact executive, this is the one to go for.
True, were still to sample the full range, but we have no doubt that this cars combination of a great drive, good accommodation and excellent economy and emissions will make it an impossible act to beat.
What Car? says