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 hatchback 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 Mazda-engineered powertrain under the hood, a 4-cylinder, 16-valves 121hp unit, while the other one gets its power and torque from a 4-cylinder, 8-valves 120hp engine designed by FIAT.

Both vehicles got tested by European New Car Assessment Programme (Euro NCAP), with the same number of safety stars gained in the process. 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? On the other hand, when it comes to weight, a factor that most people underestimate, the German car offers a marginal difference of 7% more metal.

Reliability is not the best thing to consider on the make level, but it is worth mentioning that Mazda does have a slight advantage, when all the models are taken into account. These are the official statistics, while our visitors describe reliability of Mazda with an average rating of 4.4, and models under the Opel badge with 4.2 out of 5. Some independent research have also placed 6 as average reliability-wise, and Signum is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as the Japanese car rank it on average as 4.0, while the one under the competitor's bonnet gets 4.5 out of 5.

Mazda is undoubtly more agile, reaching 100km/h in 1.2 seconds less than its competitor. In addition to that it accelerates all the way to 196 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 6.3 liters of fuel per 100 kilometers (45 mpg), in combined cycle.

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 German car offers slightly better overall protection and takes the lead. From there things take a different direction, with Mazda being considerably quicker, thus putting more smile on driver's face. It does come at a cost though, and that's the fuel consumption... It's really tough to make a final decision here, but if I'd need to, I'd say Opel. 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. 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™, out of 12.000+ vehicles we currently have in our database.