I've listed some of the common and important ones below. First, regional anesthesia is preferred over general anesthesia for cesarean section if at all possible.
Regional anesthesia takes slightly longer to perform than general anesthesia.
There are also some conditions that make regional anesthesia a poor choice where general anesthesia would be performed. Some examples of this are such things as bleeding problems, infection of the skin on the back, etc. However, if we can do regional anesthesia it is preferred. The reason for this is that general anesthesia carries with it the risk of aspiration and the risk of failed intubation - both of which can lead to death. Aspiration basically means that stomach contents end up in the lungs because the patient is too sedated or unconscious and cannot prevent it.