Are British accents or American accents preferable for ESL learners?

If you are learning English as a second language (ESL) the question of English accents, and whether you should take on a British accent or an American accent, becomes important. Most often the English language is either spoken with an American accent from the United States or with a British accent from England, but English varies immensely. British accents vary from city to city, and American accents vary from state to state, so really there is no superior or preferential English accent. There are also Canadian accents, Australian accents, Scottish accents, Irish accents, South African accents, and New Zealand accents which all have unique sounds and need to be considered when learning English.