Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by diesel engines and utilizing the 5-door wagon body style within the same 'Large family car' segment, the only major difference here really is their wheel drive configuration (4 x 4 for the Audi and rear in the case of the BMW). The first one has a Volkswagen-engineered powertrain under the hood, a 4-cylinder, 16-valves 143hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 143hp engine designed by BMW.

The first thing to look into here would be the results from European New Car Assessment Programme (Euro NCAP) tests performed on the two cars. Good thing is that both vehicles got tested, with the same number of safety stars gained in the process. That aside, let's consider some other aspects which affect safety. Both vehicles belong to the large family car segment, which is generally a good thing safety-wise, but it doesn't do much to help us decide between the two. Furthermore, if we'd like to consider vehicle mass in this context too, which we definitely should, Audi A4 offers a considerable difference of 10% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that both brands display similar results in faults and breakdowns, all the models observed together. These are the official statistics, while our visitors describe reliability of Audi with an average rating of 4.2, and models under the BMW badge with 4.1 out of 5. Independent research findings rank A4 as average reliability-wise, and 3 Series is more or less at the same level.That apart, owners of different cars powered by the same engine as Audi A4 rank it on average as 4.3, while the one under the competitor's bonnet gets 4.1 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.9 seconds less than its competitor. In addition to that it accelerates all the way to 210 kilometers per hour, 10km/h more than the other car. When it comes to fuel economy the winner has to be 3 Series, averaging around 4.5 liters of fuel per 100 kilometers (63 mpg), in combined cycle. We can't ignore that 38% difference compared to Audi A4.

Audi appears just a bit more reliable, although the difference is truly marginal. The most important thing when deciding between any two vehicles should always be safety, both passive and active. In my opinion, everything taken into account, Audi A4 offers significantly better overall protection, taking the lead here. From there things take a different direction, with BMW outracing its opponent in any situation possible, making it better choice for boy racers. To make things even better, it consumps less fuel! All together, there's not much more to say, in this case I wouldn't even consider anything but BMW. In any case that's my personal view, built upon all the data available to me. What should decide here though is the way you feel about the two vehicles, and I hope you'll find my guidelines useful in the process. In case you have two minutes to spare I invite you to define your needs, desires and budget and see which car would be chosen by the virtual adviser™, among thousands of similar, yet so different vehicles.