Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by petrol 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 front in the case of the Audi). The first one has a BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 272hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 256hp engine designed by Volkswagen.

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 that fact doesn't break the tie between the two cars. On the other hand, taking kerb weight as an important factor into account, Audi A4 offers a marginal difference of 3% 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. 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. The same official information place 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 3.0, 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 250 kilometers per hour, 5km/h more than the other car. When it comes to fuel economy an obvious choice would be 3 Series, averaging around 7.3 liters of fuel per 100 kilometers (39 mpg), in combined cycle. That's 29% 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, 3 Series offers slightly better overall protection and takes the lead. 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. 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™, out of 12.000+ vehicles we currently have in our database.