Economic Essay Question

Karl Marx argued that all value in goods and services (commodities) came from the expenditure of labor in production.  Profit, interest, and rent are therefore the results of appropriating the surplus product of workers and hence constitute exploitation of the working class.  Many economists argue, to the contrary, that entrepreneurship is a factor of production which adds value to the production process and therefore earns a legitimate return to its exertion.  How would you evaluate these two contrasting views, and what are their implications for society?