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.

Scott Reilly

This plugin adds a checkbox to the profile page for users which allows them to opt into receiving a notification email whenever a comment is made to the site.
If a comment goes into moderation, only users who have the ability to manage comments on the site will receive the moderation notification email.
By default, all users of the site have the ability to subscribe to notifications about comments. A filter is provided to facilitate use of code to customize the feature’s availability to users.
Note: a “user” is a person with an actual login account for the site. The plugin does not facilitate permitting visitors who do not have an account on the site to be able to subscribe to all comments.
Links: <a href="http://coffee2code.com/wp-plugins/optin-comment-notifications/" rel="nofollow ugc">Plugin Homepage</a> | <a href="https://wordpress.org/plugins/optin-comment-notifications/" rel="ugc">Plugin Directory Page</a> | <a href="https://github.com/coffee2code/optin-comment-notifications/" rel="nofollow ugc">GitHub</a> | <a href="http://coffee2code.com" rel="nofollow ugc">Author Homepage</a>

Optin Comment Notifications

Checkboxes on user profiles to receive emails about new comments. Like it says.

Exactly what you want

Allows users to opt into receiving a notification email whenever a comment is made to the site.

WP Simple Notify vs Optin Comment Notifications