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 4-door sedan 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 218hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 177hp 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, if we'd like to consider vehicle mass in this context too, which we definitely should, Audi A4 offers a marginal difference of 6% 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, when all the models are taken into account. That's the official data, while our visitors describe reliability of BMW, as well as Audi, with the same average rating of 4.2 out of 5. Some independent research have also placed 3 Series as average reliability-wise, and A4 is more or less at the same level.That apart, owners of different cars powered by the same engine as 3 Series rank it on average as 3.2, while the one under the competitor's bonnet gets 3.9 out of 5.

BMW is undoubtly more agile, reaching 100km/h in 1 seconds less than its competitor. In addition to that it accelerates all the way to 245 kilometers per hour, 17km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 5 liters of fuel per 100 kilometers (57 mpg), in combined cycle.

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! No mistake, whatever you decide here, but I'd still go for the BMW. Anyway, that's the most objective conclusion I could've came up with and it's based solely on the information found on this website. Aspects such as design, practicality, brand value and driving experience are there for you to measure them out. 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.