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 (rear for the BMW and 4 x 4 in the case of the Audi). The first one has a BMW-engineered powertrain under the hood, a 4-cylinder, 16-valves 184hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 170hp engine designed by Volkswagen.

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. Moving further on, let's take a closer look at some additional safety-related facts. Both vehicles belong to the large family car segment, which is generally a good thing safety-wise, still it doesn't help us solve our dilemma, does it? On the other hand, taking kerb weight as an important factor into account, Audi A4 offers a marginal difference of 8% more metal.

Reliability is not the best thing to consider on the make level, but it is worth mentioning that both brands display similar results in faults and breakdowns, all the models observed together. That's the official data, while our visitors describe reliability of BMW with an average rating of 4.1, and models under the Audi badge with 4.2 out of 5. Independent research findings rank 3 Series as average reliability-wise, and A4 is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as 3 Series rank it on average as 3.8, while the one under the competitor's bonnet gets 4.2 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.5 seconds less than its competitor. In addition to that it accelerates all the way to 228 kilometers per hour, 8km/h more than the other car. When it comes to fuel economy the winner has to be 3 Series, averaging around 4.9 liters of fuel per 100 kilometers (58 mpg), in combined cycle. We can't ignore that 18% 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 slightly better overall protection and takes the lead. From there things take a different direction, with BMW being considerably quicker, thus putting more smile on driver's face. To make things even better, it consumps less fuel! It's not difficult to say then that if I'd need to make a choice, it would definitely be the 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™, out of 12.000+ vehicles we currently have in our database.