What are the Drawbacks to IMAP?
Unlike POP3, IMAP requires continual access to the server during the time that you are working with your mail. Also, because the messages are stored on the server, it becomes much easier to go over your disk quota. However, you can reduce this risk by taking specific steps to not leave your Sent Mail, Drafts or Trash on the server. And like any new service, there is a slight learning curve to get used to IMAP since most people are used to using POP3.