IMAP is now a Gmail feature, it’s not yet available in all the accounts but should be in the next 2 days (I already have it :P). IMAP is better then POP since the changes you make to your mails will be applied on all platform so a message you already read and answered will show as read and answered wherever you access Gmail from.
I usually keep Gmail open in a tab in FireFox since I didn’t like the way it worked before on Outlook with POP, so I am going to retry it using it with Outlook and see if it’s better then the Web Version.