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 (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, 8-valves 110hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 136hp engine designed by BMW.

Both vehicles got tested by European New Car Assessment Programme (Euro NCAP), with the BMW being a slightly better choice apparently. 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. On the other hand, taking kerb weight as an important factor into account, 3 Series offers a marginal difference of 1% 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, at least on all of the models level. That's the official data, while our visitors describe reliability of Audi, as well as BMW, with the same average rating of 4.2 out of 5. The same official information place A4 as average reliability-wise, and 3 Series is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as Audi A4 rank it on average as 4.5, while the one under the competitor's bonnet gets 4.4 out of 5.

BMW is undoubtly more agile, reaching 100km/h in 2.1 seconds less than its competitor. In addition to that it accelerates all the way to 207 kilometers per hour, 15km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 5.8 liters of fuel per 100 kilometers (49 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, 3 Series offers much better overall protection, which launches it ahead of the other contender. It all continues in the same direction, with BMW being considerably quicker, thus putting more smile on driver's face. 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 more than 12.000 different ones in our database.