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 BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 184hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 150hp 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. 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? Furthermore, when it comes to weight, a factor that most people underestimate, 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, all the models observed together. 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. Independent research findings rank 3 Series as average reliability-wise, and A4 is more or less at the same level.Above it all, drivers of cars with the same engine as 3 Series rank it on average as 5.0, while the one under the competitor's bonnet gets 2.3 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 thousands of similar, yet so different vehicles.