Claws Mail Client

Thunderbird has been performing so badly that I've switched to Claws. The important features for me from Thunderibrd were satisfied by Claws:

• Quick response (Thunderbird was getting too slow)
• IMAP/SMTP over SSL
• Threaded View
• Emacs as my editor
• GPG Plugin
• Support for Zimbra tags
• Easy view of mail headers
• Some type of scripting support (Python and Perl)

It also has a calendar plugin I might try; I've been sticking with Zimbra webmail for calendars/contacts.

On Fedora you can easily install it with its plugins:

yum install claws-mail
 claws-mail-plugins-smime
 claws-mail-plugins-pgp 
 claws-mail-plugins-python