Maybe they are better now, but I had two Mazdas between about 2005 and 2015. They were fine for the most part, but their frames rusted out and had to be scrapped well before the rest of the car was worn out. They're not really suitable for long-term use in the midwestern/northeast US salt belt unless you're a high-roller who only leases cars.
Yes, but the Mazdas we had were worse than average. They were made of thinner gauge metal than I've seen on any other car (both frame and body panels) and I they didn't bother to add even a token amount of paint or other rust prevention.