Ranked in these QuestionsQuestion Ranking
Pro Beautiful interface, customisable to your needs
Pro Calendar inclusive
Pro Chat included
eM Client includes integrated chat, so you don't need another application for chatting with your friends. All common chat services supported (Google chat, Jabber and others).
Pro Free and paid version
It is free for 2 accounts and as long as you don't use it commercially. Paid version comes with support and can handle more than 2 accounts.
Pro A perfect companion to your Gmail or other webmail you might have.
Pro Very fast
Con Poor integration with Yahoo Mail
Integrations with a Yahoo Mail account doesn't always work well in eM Client.