Each natural stone is unique and comes with its own characteristics. While some natural stones such as marble are harder than other stones, some stones are softer or shinier. Thus, it is not possible to compare these stones to each other without any context.
If you are looking for flooring with heavy foot traffic, marble will be a better choice for you. On the other hand, if you are planning to cover your walls with a natural stone tile, then marble will be an expensive option and you need to prefer limestone. Depending on your application, there are some design preferences of some type over another. For example, limestone tiles are not suitable for high-traffic areas but will be perfect for wall applications.
Another factor you may want to consider is the wetness. While some natural stones have high resistance to wetness, some may require finishes such as honing before the application and some of them are not suitable at all.
StoneTileDepot.com only carries stone tiles and decorative natural stone products, which are suitable for interior or exterior floors and walls.