Well, these are two pretty similar cars we have here! It's only details that could potentially make the difference. Considering they both belong to the large family car segment and utilize the same 5-door wagon body style and the 4 x 4 wheel drive system, it all comes up to the specific diesel engine choice they offer. The first one has a Volkswagen-engineered powertrain under the hood, a 6-cylinder, 24-valves 150hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 184hp engine designed by BMW.

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 BMW being a slightly better choice apparently. Still, apart from the official crash test results there are other things we need to be aware of. 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, if we'd like to consider vehicle mass in this context too, which we definitely should, 3 Series offers a considerable difference of 12% 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, when all the models are taken into account. These are the results of an independent reasearch, while our visitors describe reliability of Audi, as well as BMW, with the same average rating of 4.2 out of 5. Some independent research have also placed A4 as average reliability-wise, and 3 Series is more or less at the same level.Above it all, drivers of cars with the same engine as Audi A4 rank it on average as 2.3, while the one under the competitor's bonnet gets 5.0 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.9 seconds less than its competitor. In addition to that it accelerates all the way to 221 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 7.8 liters of fuel per 100 kilometers (36 mpg), in combined cycle.

BMW is apparently more reliable, not too much, but just enough. 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 beats the other contender by far, making it the best choice without even considering other things. It all continues in the same direction, with BMW offering somewhat better performance, just enough to call it quicker. Fuel consumption is more or less the same. 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™, among more than 12.000 different ones in our database.