CNAs generally work either in nursing homes or hospitals. I think there is better working conditions in most hospitals, versus that of nursing homes. I am not 100% sure about that, it is just my impression.
Some of the nursing homes I have seen are real slave pits. To save money they do not hire enough CNAs, so those that are there have to work extra hard to make up for the lack of CNAs.
Plus, if the hospital is large enough, you have greater opportunities for promotion later on.