I was never a fan of Apple's mail program but was never sure how weak it was until I was forced to quit using Eudora when switching to Lion. I made the first of the year the day to start. After all, Eudora has been abandoned since 2002 and was getting very creaky under Snow Leopard. It was always an extremely powerful program, with all kinds of hidden settings and tricks it would do. Now that they are gone I really miss them.
1) You cannot edit the Subject line of incoming mail. Highlight text and hit Delete just moves the entire message to the Trash.
2) Keyboard shortcut to the next message. (In Eudora, it's command-right arrow and command left arrow to move backwards. Command up-arrow and down-arrow do the same thing.) I can't believe they left this out!
3) Edit the text of an incoming message. Suppose I want to archive a message but it's filled with a dozen paragraphs of quoted old messages. Simple button to enable in Eudora but nothing in Mail.
4) No Transfer menu. I have to close a message and drag it to an archive mailbox. There is a similar function if I right-click the message, though. I'll give it that.
5) Even with the help of AppleCare techs, I could not make it work with a POP connection to Gmail. No problem for Eudora, Mail would work with IMAP only. While it has its uses, I have never been a fan of IMAP, which will not show your messages if you disconnect from the Net. Under POP, mail is downloaded and stored on your Mac. My regular moonmac.com account works fine as POP.
There are a few things it does right:
A Command + or - enlarges or shrinks the message type. HTML messages filled with graphics and links display correctly. Eudora was never designed to do this. Just typing a name in the TO field will autofill if the name is in the Address Book. Eudora can also do this.