Comparison between Weber and Marx
Both Marx and Weber are critical to modern capitalist society, but Weber's theory is moderate to some extent (and thus often easy to accept politically), while Marx is more radical politically.
Weber studied people's idea, while Marx focused on (economic) structure.
Most of Weber's work derived from detailed historical study. Thus it sounded very scientific and academic. Marx also did much serious research, but his way of writing was often too critical.
Lastly, Weber offered broader approach (religion, law, the city, or even music) for the analysis of the social world, than Marx's narrow focus on the economy.