The interface looks simple and is not that attractive, but it has an intuitive design and is customizable; you can choose between lots of themes and change layouts and toolbars. The Bat! has an email filtering system that allows you to sort messages into folders or into groups and to add group colors in order to track them faster and better. It also has complex templates for the address book or for each account, a built-in search engine, a spell checker, a Mail Ticker that announces every new email even when the program is minimized to tray and a Mail Dispatcher that is really useful when you are unable to download large messages. But what I consider to be really practical and I speak from an average user's point of view, is the Smart Bat, which is a small editor that allows you to save notes and integrates also a scheduler.
The Bat! is a flexible email client. It is complex and easy-to-use at the same time, has lots of practical features and can import messages from Outlook, Communicator, Netscape, Eudora and Pegassus.