What's the difference in the three ? When/why would you use one and not the
other...?

I am going to create a little drainage area around my downspouts with river
rock type pebbles and one of the above cements as a base to carry the water
away and on to an underground drain pipe grid.

Which of the three 'cements' would be best and why ? there will be little
stress on these "spillway" type slopes leading to the in-ground drains

Thanks, Tim

p.s. Live in Phoenix...no freeze thaw here in winter