Jeff zone 8 N.C.

Terracotta would be better for air and drainage as those pots breath through the wall and will dry out faster (maybe too fast). If you try to remove the plant from the pot as a entire root ball they might tend to stick in the pot a little as opposed to plastic. Also if you are in a windy area they will be heavier and so when the plant gets bigger they will help with keeping it from falling over and breaking leaves. Plastic would be fine though as long as you use the well draining soil and are attentive about the moisture levels.