Ranked in these QuestionsQuestion Ranking
Pro 100% free (at the moment)
The company earns (enough) money with affiliate links, therefore there is no need for a purchasable pro membership.
Pro Follows strict privacy rules
Because it is located in Germany, the company has to follow very strict rules regarding privacy.
Con Uses affiliate links which can be seen as an invasion of privacy
Affiliate links are usually not only a way to earn money with advertisement, it mostly also includes generating user profiles which could be seen as a big privacy issue.