Pegasus Mail is a professional e-mail client that covers all the basics—spam filtering, chess-board stationery, send/receive—while keeping the interface clean, uncluttered and easy to master.
What makes it different
Pegasus gives you industrial-strength filtering: create rules that auto-reply when a keyword is in the subject, play a sound for urgent mail, or generate “out-of-office” answers for specific senders. The only trade-off is the retro icon set—you’ll need to hover and try them to learn what each button does.
Pegasus provides a great filter control mechanism for you to automatically process incoming emails. You can create rules to do a lot of things: send prepared e-mail replies based on keywords in the subject line; let the client side software sound when urgent emails arrive; and automatically create "I'm not here" reply messages for different email senders.
Using Pegasus Mail, you obviously feel that its interface is different: all the icons are the old style, and you have to try to understand the functions of the icons yourself. This is the biggest drawback of Pegasus Mail.