MailPoet

Yes, we’re actually a good alternative to MailChimp.
Why? Your clients can send newsletters with their WordPress content without fighting the machine.

For deliverability, simply connect our plugin to Mandrill, SendGrid or Amazon SES.

A few fun facts:
Over a million downloads on the repository
Installed on nearly 100,000 websites
We’re in the top 10 most popular plugins
We’re a team of 9 folks
Our plugin abides to German laws