I have used Eudora since the mid 80's and although it is far from perfect, I would not swap it for any other mail program. I am relieved to find that this new version now allows me to use the Mac OSX address book. I wish it were the only thing it would use!
What I sorely need, however, is to be able to have a drop-down menu of alternate email addresses for an individual. I find I have to guess at nicknames to see if they expand to the correct address. Occasionally I just give up and open the address book.

Another problem that I have is the "smtp relay personality". I have nine email accounts on five different servers. Some require authentication, one requires pop before smtp. There seems to be no good way of reliably switching from one smtp server to another - a job I often have to do 2-3 times a day as I visit different offices. If ONLY Eudora could read the "location" information in my Apple menu and select the appropriate smtp server......

I also wish there were a simple way of changing between "Send" and "Queue" for outgoing mail - sometimes I am on a modem and sometimes on wireless and it is frustrating to see error messages spawning when I happen to be offline but Eudora is active. Surely it could check to see if an internet connection is active before trying to send or pick up mail?

Overall, I think the program is fair value for the money and I will continue to support it if the developer will make these needed changes.