For the email service to be a success it should be faster and secure. Rediff is the fastest ever mail service I found.I do not know about the security issues in this. Hotmail is the contradictory mail service to this. By the time it takes for reading one mail and replying at Hotmail, we could finish more than 10 mails at Rediff.
But on some rare occasions it takes very long time to open or does nerver open and not possible to add any attachments. Also the space(MB) that is provided for attachments in a mail is less compared to other mail service.