Which is better Entity or Primitive?

Hi all.
Now I’m building Airplane tracking application on mac.

I planed to put and move over 500 objects on cesium

in this case Which is better model as entity or primitive?

I have not yet understood the difference of both.

thx.

The short answer, Entities, but see this tutorial for a lot more information: http://cesiumjs.org/2015/02/02/Visualizing-Spatial-Data/