They are the same, but come in a number of different grades.

Base compound is heavier than topping compound.

It is actually pretty rare to need to add water if you mix up the container thoroughly before using it .

Setting type compounds come as a powder in around 20 pound bags and must be mixed thoroughly and smoothly with water before use.
They harden by chemical reaction (as opposed to drying like the pre-mix stuff) and if mixed correctly have far less shrinkage as they set.

The far lower shrinkage is enough to make Easysand worth using for screw dimples, let alone seams.
If you are inexperienced buy a longer setting time.

Easysand20 is for experienced folks.

Thanks for the help! We scraped parts of the chipping plaster off the ceiling of our bathroom, house was built in 1968. The bare "Green board" is exposed, can I use a ready mix joint compound on the ceiling and try to replicate the "swirl" texture look, or use the powder form and work fast.
Both results will be painted.
Thanks

"use the powder form and work fast. "

The setting compound would be much better.

"Easy Sand 5, 8-12 minutes; Easy Sand 20, 20-30 minutes; Easy Sand 45, 30-80 minutes; Easy Sand 90, 85-130 minutes; and Easy Sand 210, 80-240 minutes."

Get some of the 210 minute compound

Here is a link that might be useful: Easysand data

This post was edited by brickeyee on Thu, Jan 24, 13 at 8:57

"patient enough to apply enough coats"

Texture is often a one shot deal.

Going back to fill 'drying shrinkage cracks' may not work well depending on the texture.