Gasoline robust and reliable: Mazda6 or Opel Insignia

Hi @, I started to look for myself, but I quickly realized that this is very tough, because I really have 0 experience with petrol and the brands mentioned in the title (had so far only VW diesel, manual gearboxes). So far I have only driven motorway so about 20-30 tkm p.a., but soon so many things change for me and I will drive much less (not every day and then rather city or sometimes travel somewhere), therefore and because of diesel scandal and possible consequences I would go to Be nziner change. I am a cozy driver, was so far with about 140 hp absolutely satisfied, but what is absolutely important to me is that the cars are robust and reliable and have high comfort. In general I also see that I do not buy models that still have childhood diseases, so if it goes at least 2 – 4 years after model introduction etc. I would buy a car Built. approx. 2014, automatic. What would you say Insignia or Mazda6 would be less susceptible to general Probl eme, rust, automatic transmission problems, childhood diseases or other problems? What about driving comfort etc? If one or the other brand, which motorization and what would be the advantages? I will probably have to make the same request in the Insignia forum.