As with most things in life, there are advantages and disadvantages to each material. The first important step is not to confuse the two finishes with each other. Stucco is defined by Webster's dictionary as "an exterior plaster made of cement, lime and sand." While stucco is a natural cement product, acrylic finish is a synthetic man-made coating. Stucco cures to a hardened state while acrylics dry to their final hardened state. This is a critical difference when considering environmental conditions during application.
Regions of Canada and the United States seem to have a preference to one or the other finish coat material for Portland cement plaster bases. For example, traditional stucco finishes are much more popular in Southern California, while acrylic finish coat is more popular in Seattle. Vancouver, B.C., seems to have a fair mix between acrylic and stucco.