Rakib Hossain

The easiest to use rating option in comment! <a href="http://www.rakibhossain.cf/comment-rating" rel="nofollow ugc">Fa Comment Rating</a> plugin allows you to add a rating field in your comment from. Rating would be visible after comment content.
You can modify user comment rating by your dashboard comment screen.

Fa Comment Rating

Adds an awesome rating field in comment form.

elpix-GmbH

Star rating for posts and pages integrated in comment-functionality of wordpress. This plugin uses the 5-Star-System. 
Use the shortcode [elpix_average_rating] in your content to show the average rating of the post or page.

elpix Rate Post in Comment

Star rating for posts and pages integrated in comment-functionality of wordpress.

Fa Comment Rating vs elpix Rate Post in Comment