It’s the most popular and most hated newspaper in Germany. I would put it at a similar level as Rupert Murdoch’s shit rags.
They usually have dubious journalistic standards, write exaggerated headlines and harass their targets. They also constantly badmouth progressive or environmental causes because their shitty publisher, Axel Springer Verlag, has a very imperialist neoliberal agenda that they enforce in all their publications. I blame them in part for the popularity of AfD, even though they don’t directly endorse them (as far as I know).