When comparing Seamonkey vs eM Client, the Slant community recommends eM Client for most people. In the question“What are the best e-mail clients for Windows?” eM Client is ranked 8th while Seamonkey is ranked 14th.
Ranked in these QuestionsQuestion Ranking
Pro Not just an e-mail client
Seamonkey is more than just an e-mail client as it is a full featured web browser as well. This makes for a good app to use for those that dislike having many different apps on their devices as it is a bit like an all in one solution.
Pro Auto imports setting from Thunderbird
For those that would be making the switch from the Thunderbird e-mail client setup is quite easy with Seamonkey as it auto imports all previous Thunderbird settings.
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 Permanent CPU usage
Seamonkey permanently uses CPU (quite a few percents on a Intel i7). On a laptop this causes the fan to run (which make noise) and the battery to lasts less time.
Con Muy lento al procesar varias cuentas de mail
Cuando se programan varias cuentas de mail se vuelve insufriblemente lento, al punto de tildarse el programa y tener que reiniciarlo. El sistema donde está instalado es bastante potente (Intel i5, MB Asus, 16 GB Ram) y aún así va muy lento. No ocurre lo mismo cuando está configurado con una sola cuenta de mail.
Con Poor integration with Yahoo Mail
Integrations with a Yahoo Mail account doesn't always work well in eM Client.