eM Client is a full featured email client with a modern and easy to use interface. It offers calendar, tasks, contacts, and chat; supports major email services including Gmail, Exchange, iCloud, and Outlook.com; easily imports your data from most of the other e-mail clients, including Microsoft Outlook, Outlook Express, Windows Mail, Windows Live Mail, Thunderbird, The Bat, and others; fully supports touch devices like touch-enabled laptops, tablets and hybrid devices; and finds any email, contact or attachment in seconds with eM Client's search.
eM Client's security features include secure communication via SSL/TLS and message encrypting via S/MIME. It also features advanced email rules management, conversation view, application-wide spell-check, and a built-in email translator for incoming and outgoing messages using Bing Translator.
All of these features are well and good, but at the end of the day, eM Client is a freemium product. Fully free and open source alternatives to eM Client can provide many of the same robust functionality that eM Client offers, and any missing functionality can potentially be implemented via apps with support for extensions.