cmake has by far the biggest following. I am using hunter because I know it and it works for me.
However if you write cmake avoiding bad practice etc your code can be incorporated into most cmake package managers with very little effort. I am not a cmake expert by any sense of the word, however for every C++ library that I am using I am making a compliant cmake file so that it keeps my main project clean, and the packages reusable for other projects that I want to use in the future. So the secp256k library that I have done should work in conan with little or no effort.
