My answer was to go with what I liked. From what I understand- some varieties will be heavier as they are more dense- colors can depend on what area and region they came from as well as the conditions in your tank- shape and size are big factors when choosing different styles. I would look as much as you can and pick types that you like the looks of and go from there. As far as I know there is not a big difference or overwhelming factor between different types of natural reef live rock when it comes to filtration. Someone please correct me if I am wrong and I hope this helps some