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 front 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.

A starting point here would be to take a look at the results from European New Car Assessment Programme (Euro NCAP) tests which were performed on both of the cars, 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, but it doesn't do much to help us decide between the two. On the other hand, when it comes to weight, a factor that most people underestimate, Audi A4 offers a marginal difference of 4% 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, at least on all of the models level. 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. 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 3.8, while the one under the competitor's bonnet gets 4.2 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.8 seconds less than its competitor. In addition to that it accelerates all the way to 235 kilometers per hour, 5km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 4.9 liters of fuel per 100 kilometers (58 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. Also, you could use the oportunity to find out which car, everything taken into account, would be the perfect choice for you in the eyes of the virtual adviser™, among more than 12.000 different ones in our database.