what are they? which is better? how do you make it?

they are 2 separate things.

Poured icing recipe can probably be found on a search or in recipes.
This is thinner runny consistency and is poured over the cake. I put a thin layer of buttercream on so it looks smoother.
Satin ice is a rolled fondant, like a dough, you roll it out and drape it over the cake. I prefer the look and ease of use of satin ice and the taste of poured fondant.

It also depends on what you are making.

HTH