The thing that differentiate Soundcloud from all the competitors you are mentioning is the social network that it's build on. Hence the size of the catalog that

The thing that differentiate Soundcloud from all the competitors you are mentioning is the social network that it's build on. Hence the size of the catalog that is by far (3.5x) bigger. In other words, if you want to find something completely exclusive and never heard before, Soundcloud is the place to go. If that content is good quality or not, is another topic :)