A comparison of scalable database isolation levels is presented in the article, highlighting the challenges of accurately describing isolation guarantees offered by modern distributed databases. The study ranks databases by their maximum multi-partition isolation level and provides a neutral characterization of various systems' architectural properties. It also discusses the implications of different isolation levels and how they can impact application developers, particularly in microservices architectures. The article concludes that a good way to think about isolation is in terms of the breadth of potential anomalies, and it encourages readers to critically evaluate their current databases' transactional isolation guarantees.