Chris Baltazar

Easy to setup and get the ball rolling, you just need to fill out the common email config fields as any other webmail client
Works also for private providers like AWS SES 
After that you can just select the desired evens to be notified about and that’s it
Manage everything from a single and very dynamic admin screen in your dashboard and get the plugin working just in a few minutes
Just install it and then do directly into Settings / WP Simple Notify to see all the options. Enjoy it!

WP Simple Notify

It's very easy to setup and make it work, you can also make a test for your configuration and goes smoothly with all comment notifications

Super simple and efficient

Easiest WP Plugin to manage email notifications for common events such as user's post comments.

Gagan Deep Singh

guillaumemolter

livearoha

This plugin enables WordPress blogs of any size to deliver and track WordPress notification emails reliably, with minimal setup time and zero maintenance. No more SMTP errors or delivery problems with Postmark!
If you don’t already have a free Postmark account, you can get one in minutes. Every account comes with thousands of free email sends.
PLEASE NOTE: This is not official PostMarkApp Plugin. This plugin is a copy of the Official Postmarkapp plugin which had several critical bugs. The Official Plugin developers have not addressed these bugs for some time now, so I created a new plugin to solve those issues.
Issues fixed(from the official version):
<ul>
<li>Fixed the Connection Timeout bug</li>
<li>Fixed the Fatal Error due to incorrect usage of WP_Error object</li>
<li>Fixed the issue while parsing the headers sent as array to the wp_mail function</li>
<li>Fixed the breaking of plaintext when force html option is selected</li>
</ul>
New Features added:
<ul>
<li>Support for adding Cc, Bcc, and Reply-To headers</li>
<li>Support to filter the arguments by other plugins like its done in the actual wp_mail() function of WordPress</li>
<li>Auto import settings from the Postmarkapp approved WordPress plugin for easy migration</li>
</ul>
Roadmap:
<ul>
<li>Support for attachments</li>
<li>Handling special characters in Subject</li>
<li>Ability for dynamic “From” addresses by verifying from PostmarkApp</li>
</ul>
To know more about PostMarkApp, please visit this link: http://postmarkapp.com
To get help about PostMarkApp, please visit this link: http://support.postmarkapp.com/

PostmarkApp Email Integrator

Enables your WordPress site to send emails via PostMarkApp API.

WP Simple Notify vs PostmarkApp Email Integrator