If trying to decide upon which of the two for your event, here are a few helpful tips.
Although fondant is the most elaborate of the two, it is also the most costly. Whether it is homemade of store bought, most people will not eat it. Fondant is mostly peeled back from the cake. The most advantage that it has, is for maintaining the cakes freshness. Due to its texture, fondant should not be cut as one would cut a buttercream cake. By doing so, will surely cause the delicate cake underneath to crumble. Fondant base is made of marshmallows, which makes it very sweet. Always use the sharp tip of the knife in order to pierce through the fondant. Also, fondant will make a much safer delivery due to its firm texture.
Buttercream as we know is just that, buttery and soft. This icing is for taste. Make certain before a delivery, you have allowed the icing to crust. This is crucial in order to keep the buttery icing from melting. Also, Handle with care, fondant is much more forgiving with accidents. Just remember the main rule: Taste, buttercream. Elegance, fondant!