Usually some people get confuse when they find two options for getting their emails on some application on mobile or computer (thunderbird or outlook etc). They don’t know which one they should use and get stuck between POP and IMAP. Popular email services like Gmail and Outlook support IMAP and POP. Outlook did not support IMAP till two days ago but now it does. (Read also: How to configure thunderbird for Outlook through IMAP)
No one can say that one protocol is better than other because both of those have their own benefits. [You may also like: Get Facebook chat on desktop]
Post office Protocol (POP):
Post Office Protocol also known as POP came up in 1984. When you connect applications through POP protocol they download all new emails from your server inbox, delete them from there and store them on your local computer.
Should I use it?
This is not better for you if you want to get your emails on multiple devices because they are deleted by application which you used for downloading emails. There are also apps like thunderbird which give you option to keep mails on server without deleting them. Mainly this is for those users who don't want to keep mails on server because of storage issue or for those who want to get their emails on single device.
Internet Message Access protocol (IMAP):
Internet Message Access Protocol also known as IMAP was developed in 1986. If you connect applications using IMAP they'll get emails and also folders as you have on your email server. Every time you navigate to some other folder application will connect to your server, will refresh content of that folder and show that to you.
Should I use it?
You can use this protocol if you want to download your emails on multiple devices because it’ll not delete emails from server unless you delete them from your server manually within the application or from web interface. You can refresh folders to get any changes made to any mail from other applications or devices. This is good for those who don't care about storage on email server or have limited space on their machine. Also this needs an active internet connection.
I hope this little explanation will help you choose protocol that is best for you. If you have anything to share please post that in comment.