A3 I drove.
First of all, from the exterior it is a handsome car with the right creases in the sheet metal and the correct aggressive lines in the front fascia. The daylight running lights are some of the coolest looking I've ever seen. I enjoyed seeing their reflection in shop windows when I would park.
The interior is not as impressive with cheap-looking materials that might have come from the VW parts bin. The infotainment screen was permanently stuck to the front of the dash like an after thought. It could be turned off, but that was all. I know Audi likes its infotainment screens to pop out of the dash. This one didn't, just looked like it did. I'm not sure if the wood was fake or just looked fake.
The car didn't have a navigation system installed (even though it had buttons for one), so I wasn't able to evaluate that. European cars are infamous for having speedometers read high. And this one was, according to the GPS speed app on my phone, no exception. The speedometer read two miles per hour high.
The start engine button was in a strange, almost hard to reach place near your right knee. And the car had that stop-start function that most (if not all) new Audis have. When you stop the car at say a stop light, the engine shuts off to save gasoline. I learned (eventually) that if I ignored it, it worked best. The engine would turn on when you lift your foot from the brake. But then I would wait for it to start before putting my foot on the accelerator. If I just moved my foot to the accelerator, the engine was always on by the time I got there. So by the end of the week, that's what I was doing. Also, when you put the car in park, the engine would stop. I don't know how many times I almost got out of the vehicle when it was still "on" because the engine was off and to me, that means the car is off.
The seats were leather and reasonably comfortable. The car rode like a larger car unless the road turned rough, then you could feel its size. Like all Audis, it seemed to be carved from a single block of steel it was so solid.
The base A4 has front will drive and a manual transmission. The one I drove had Audi's Quattro all-wheel-drive system and a smooth seven-speed automatic. The automatic did its job with little fuss. It had a sport mode that always put the RPMs in the power band. This was useful for passing.
The engine, a 2.0 liter turbo-charged four cylinder had 252 horsepower which for this size car, was plenty but not excessive. The engine sounded good until you got it near the red line when it turned buzzy.
The car I drove was the "Premium Plus Quattro" model which came with a Bang & Olufsen sound system with 19 speakers. From the driver's seat I could count 11 without looking in the rear-view mirror (then I could see 13). I don't know where the other six were, probably in the rear doors. It sounded amazing playing classic rock or classical music. I didn't see any place to put in a CD. But the radio worked very well, picking up FM stations from quite a ways away (there was no satellite radio other than the preview channel).
The biggest drawback of the car, for me, was it was too small. It had four doors and a back seat but it would be tough putting adults in that space, unless they didn't have legs.
All in all I enjoyed the car. I could see buying it or maybe its S4 cousin (same car, bigger engine) if I didn't need to put adults in my back seat.
UPDATE: there is no S4, which is too bad because I think that would be a really cool car.
UPDATE 2: The S4 is coming.