From Colin Leroy:
Claws Mail is a based on GTK+ fast, versatile email client. The appearance and interface are designed to be familiar to new users coming from other popular email clients, as well as experienced users. Almost all commands are accessible with the keyboard. It features quick response, sophisticated interface, easy configuration, intuitive operation, abundant features, extensibility, robustness and stability.
What's new in this version:
Version 3.9.1 has added 3 new command-line switches.
Pain to setup new accounts Won't create New Account inbox Options outdated
Claws isn't all bad, but it is antiquated. It is like working with Eudora, from 1999. Setting up new accounts is a complete pain. All info must be put in manually, unlike, for instance, "Dream Mail," that is a snap. Once you set up a new account, it will not create an Inbox for said account. I got frustrated with trying to play with the setup, and opted for a far better client. Try Dream Mail, or Post Box Express. They are both a snap to set up, and practically fill out info on gmail accounts automatically.