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 4-door sedan body style and the front wheel drive system, it all comes up to the specific diesel engine choice they offer. The first one has a Hyundai-engineered powertrain under the hood, a 4-cylinder, 16-valves 141hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 150hp engine designed by Mazda.

The first thing to look into here would be the results from European New Car Assessment Programme (Euro NCAP) tests performed on the two cars. Good thing is that both vehicles got tested, with the same number of safety stars gained in the process. 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. Furthermore, if we'd like to consider vehicle mass in this context too, which we definitely should, the Korean car offers a marginal difference of 7% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that Mazda does have a slight advantage, when all the models are taken into account. That's the official data, while our visitors describe reliability of KIA with an average rating of 4.6, and models under the Mazda badge with 4.4 out of 5. The same official information place Optima as average reliability-wise, and 6 is more or less at the same level.Above it all, drivers of cars with the same engine as the Korean car rank it on average as 5.0 out of 5, exactly the same as the other one.

Mazda is a bit more agile, reaching 100km/h in 0.4 seconds less than its competitor. In addition to that it accelerates all the way to 210 kilometers per hour, 7km/h more than the other car. When it comes to fuel economy the winner has to be the Japanese car, averaging around 3.9 liters of fuel per 100 kilometers (72 mpg), in combined cycle. We can't ignore that 18% difference compared to the Korean car.

Mazda 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, the Korean car offers slightly better overall protection and takes the lead. From there things take a different direction, with Mazda offering somewhat better performance, just enough to call it quicker. To make things even better, it consumps less fuel! It's not difficult to say then that if I'd need to make a choice, it would definitely be the Mazda. Nevertheless, let's not forget that people have different preferences and needs, so what really counts is your personal feel. I'm only here to help. 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.