Advantages of Royal Icing

• Royal icing is a simple recipe of icing sugar, water and merienge powder. It can be tinted to any color you wish using ordinary food coloring. With the proper icing tips, many different effects are possible. Using it is easy. Just outline the cookie with the icing, and fill it in if you wish. Also, royal icing can be used as "glue" for other decorations, such as sprinkles, candies or dragees. Royal icing is also deliciously sweet.
  
  

Disadvantages of Royal Icing

• Decorating hundreds of cookies can be hard on the joints.Jupiterimages/Photos.com/Getty Images
  
  Royal icing can be difficult to manage. It can be hard to get the right amount of water in the sugar mixture to make it easy to work with. If it is too dry, it won't spread properly, and if it is too runny, the icing will slide off the cookie and take a long time to dry. You must buy special tips and bags to use with royal icing, and this cost can add up. Finally, if you are doing many cookies, it can cause discomfort in the hands and wrists.
  
  

Advantages of Fondant

• Fondant is a smooth and thick covering that is usually associated with fancy wedding cakes. It is a mixture of sugar, water and cream of tartar. It is available in many pre-mixed colors for good versatility, but it can also be tinted to any color of your choosing. Decorating cookies with fondant requires only a rolling pin and either a knife or a cookie cutter. You can cut fondant to any shape, or you can mold it with your fingers to make any object from curling rocks to flowers. You can then create cookies for any party theme.
  
  

Disadvantages of Fondant

• While pre-mixed colors are available, they may not be the colors that you need for your cookies. You might have to tint the fondant yourself. This is not easy, you must use special food coloring paste, and you will have to knead the color into the fondant with gloved hands. It takes time and effort to get the color mixed evenly. To make special decorations, such as flowers, you need skill and possibly formal instruction. Another disadvantage is that not everyone likes the taste of fondant, and may end up peeling it off the cookie before eating it. To make fondant stick, you have to make royal icing to "glue" the fondant to the cookie, therefore it takes extra ingredients and time.