HeavyMail is awesome! I've been using it for a long time now, mostly for all my clien't who can't seem to get the hang of ftp. It makes transferring large files so much easier.

I saw that someone compared HeavyMail to yousendit.com. It's NOT really the same. HeavyMail securily sends your files directly to your recipient. Yousendit emails a link to your recipient and they go download the files, and I don't think yousentit is secure. Also, another huge feature if HeavyMail is delivery notification. You always know that your recipient has received the files.