Best uses for POP Accounts:
When you have a limitation on available disk space.
When you are going to do your own mail backups.
If you are only going to access your mail from one device.
Best uses for IMAP Accounts:
When you want to access your mail from more than one device.
This setup will use an increasingly large amount of storage space (Mail will not be deleted off the server and will build up over time, mail must be deleted from you mail program to free up storage space).