MaiChimp has always been my favorite email plugin but this new plugin may change the way I look at Mailchimp. This is a professional email newsletter with pretty much everything that you require.
- Easy set up and configuration
- Fully customizable templates
- Template builder
- Group management
- improved SMTP
- widget interface and behavior
- support and usage docs
The plugin comes with a lot of pre-built configurable templates for you to send to your customers. WPMU Dev is a great, configurable plugin that does everything MailChimp does and more. Try it out and see for yourself.
Read the rest of the information here: http://wpmu.org/brilliant-wordpress-email-newsletter-plugin/