Actually marble is a pretty durable stone, it does not crack very easily. But the huge problem with it is that it is very high maintenance. Marble is very porous, therefor it stains too easily, absorbs moisture like a sponge if not taken very good care of. In order to keep marble tiles shiny and clean, you need to regularly polish them. You should only use special cleaners and polishers which were designed for marble, any other cleaners will definitely destroy it. In addition to the right maintenance routine you have to have a professional reseal your marble flooring every 9 to 12 moths, which can be costly. So considering marble flooring you have to decide if you really can afford the professional care and maintenance. If you do - then just go for it! One more thing to remember - if have a wine or juice, or any other colorful spill on your marble, there is a huge chance you will have to have your tile replaced (although in your case with dark color it may not be as big of an issue as with light colors).

Good luck!