The A4 is beautifully screwed together. There isn't a shake, a squeak or a rattle to be heard anywhere, over any surface. It's very quiet and refined, and comfortable to be in. On the right road, the handling is superb. It corners flat and feels very safe doing so. At the same time, the car is too light, meaning it bounces alarmingly over uneven surfaces. Imperfections in the road cause the car to jump off line.
At high speed, poor road surfaces are nothing short of worrying, and the car has a habit of skipping off track. Undulating roads are a nightmare, and you find yourself going from having your spine compressed into the seat to bashing your scalp on the headlining. It's really not the most calming of experiences.
The multitronic or continuously variable transmission (CVT) box is a nonsense, and has caused the car to break down on four separate occasions. As it lacks gears it is very smooth around town, but when pushed it makes the engine sound strange and raucous. There is also an annoying pause when moving from forward to reverse gear. Performance is sluggish. Pickup at high speeds isn't worth writing home about. Given the choice, I would have the regular automatic. The fuel consumption is on the poor side, I thought, averaging 23mpg around town. I expected 30mpg at the very least.
The brakes are perhaps the car's largest bugbear. They are over sensitive, over assisted, snatchy, and generally wooden. Sit in stop-start traffic and you'll need a neck brace by the end of it. The brake pedal is also a good two inches above the throttle, making emergency application of the anchors rather fraut: the left edge of your shoe whacks the right edge of the pedal. I know of at least one person who went for the BMW 3-Series over the A4 because of the brakes. They really are that uncomfortable an experience.
Overall, a brilliant and well engineered package let down by some fairly fundamental issues when on the road.