FastMail

Fastmail is an excellent open-source mail sender that works efficiently and boasts of an easy-to-use interface. As a tool that is built on the GNU Public License, it is perfect for users who want to experience the full range of features that comes with this license. However, it is important to note that the current version is still in its Beta stages, which means that it may not work perfectly.

To use Fastmail, you need two primary requirements: QT3 and mail command. Once you have these installed, you can easily install Fastmail on your system. All you need to do is navigate to the Fastmail directory and type in "make" to initiate the installation process.

What sets Fastmail apart from other mail senders is its exceptional speed and user-friendly interface. Even in its Beta stage, Fastmail performs remarkably well, and the bugs that come with the Beta version are minor and barely affect its overall performance.

In summary, if you need a mail sender that is both fast and easy to use, then Fastmail is the tool for you. While it may not be perfect, its features and performance make it a compelling alternative to other mail senders out there. So what are you waiting for? Give Fastmail a try today!