The overlap between cats and scalaz is gigantic idk why you seem to think they are distinct? I'd bet that the overlap between the most commonly used parts of ca

The overlap between cats and scalaz is gigantic idk why you seem to think they are distinct? I'd bet that the overlap between the most commonly used parts of cats and scalaz is even larger. The main thing scalaz has that cats doesn't is scalaz.concurrent.Task, and there are multiple typelevel-endorsed alternatives to it being worked on as well (in monix and fs2). Task is wonderful btw. fwiw we use scalaz at work and haven't upgraded to cats because it isn't ready. cats just fixed a performance bug that would have destroyed us (Map union mappend was ridiculously unoptimized compared to scalaz's). We .foldMap(/* make a small Map*/) all the time and it's one of our favorite parts of scalaz. see https://github.com/typelevel/cats/issues/1290 https://github.com/typelevel/cats/issues/1290 for the bug.