Marx said that the philosophers had only interpreted the world in various ways. He added that the point was to change it.
He seemed to be passing a value judgement on philosophy and philosophers indicating that all their work was useless. And only his work of changing the world was useful and meaningful.
Of course this overlooks the idea that he was himself having a world view, a philosophy, based on which he wanted to change the world.
Heidegger, known for his existential preoccupations critiques Marx’s criticism of philosophers in his quiet way. http://www.youtube.com/watch?v=jQsQOqa0UVc