like many things in Maya Fur is a Post effect and rendering can take very long time. the use of fur is totally up to you and the outlook you want to accomplish. There are many things that you can use Paint effects for to get the same look. When messing with fur its not like other things in Maya to get things dome like lighting, shadows animation etc. its all controlled from the fur menu. Here is an example of fur used in a field scenerio. the scale of the fur is very short, and there is about one million pieces. Took 20 minutes to render the frame at 1280 x 720.