We are adding comment ratings to our FV Thoughtful Comments at the request of one of our clients. He likes Disqus features but doesn't like entrusting his user generated content to a third party service and doesn't like Disqus page load slowdowns. A very smart guy and successful publisher.
We've experimented with Epoch and wpDisquz and have even donated to the latter. Unfortunately wpDisquz is not fast enough either on a really busy site (measured in both page views and frequency of comments).
We didn't feel like creating our own code for comment thumbs up and thumbs down as there's lots of that out there already. One of the forgotten joys of open source in this new era of all commercial WordPress plugins (thanks Woo, Yoast) is the ability to mix and meld code. To pick code to integrate into our very sleek Thoughtful Comments plugin (hey even Jeff Chandler at WPTavern likes Thoughtful Comments and he hates our demands for user centric development at WordPress ), we had to review most of the ratings and comment ratings plugins in the WordPress.org plugin repository.
What we've managed to do for ourselves here is to allow up and down votes with only a single vote once per IP and/or logged in user ID. Nifty. The plugin which helped us do this is Zaki Like Dislike Comments. We added the user ID code ourselves and improved SQL efficiency (as Google says, speed is the name of the game no matter the bleating of JetPack apologists). We also added sorting based on ratings.
We'll also improve the visuals as the garish red and green thumbs won't work for most of our client sites. We'll go with elegant up/down arrows (after trying to reduce thumbs up/thumbs down to manageable size, we found such icons do not scale down at all well). Half a million dollars of design and user testing at Disqus resulted in simple up and down arrows. We'll be getting ours from the internal WordPress icon pack to save adding additional files and keeping load times fast again.
Here are our internal notes. Please don't complain that these notes are not illustrated and that they are brief. They are internal notes. We're publishing them as if you are WordPress pro and need to pick a ratings plugin in a hurry this will give you a huge head start and save you half a day of time. If there's only a single minus limited, it means that minus is important enough for us to terminate other evaluation. The plugins are listed in approximate order of preference.
WordPress Comment Rating Plugins
+ code looks good
- doesn't show count of upvotes and downvotes separately
- if registration is required for commenting, guests can not vote, but there is no message
- uses comment_karma field, so we can't show up and downvotes separately
+ has its own table to track voting
+ shows count of upvotes and downvotes separately
- no screenshots
- limits by user IP only!
- no sorting
- ugly icons - images
- 2 SQL queries per comment!
- if registration is required, guests can still vote
- disabling the plugin removes the votes!
+ extensive options for vote logging - cookie, IP, username
- no downvote!
+ looks good
- requires some Redux Framework. More code to load, more code to go wrong. More updates to break.
- doesn't do anything prevent multiple votes
Like Button Voting & Rating
- requires LikeBtn.com account!
+ guests are prevented from voting, but get annoying popup box when clicking the link but it can't be disabled completely - still shows some error
- there are display options for up/down votes, but they don't work!
- doesn't work for comments
Iit's a new version of GD Star Ratings which was quite heavy but doing what we need. It also had security issues.
+ extensive options for IP/cookie/logged in voting limiting
- "thumbs up and thumbs down" only in Pro version
We hope the above helps you find a basic comment voting plugin for WordPress to your own tastes. A new Thoughtful Comments version with comment rating and comment sorting by date and rating will be coming soon, adding to its existing front end editing and and comment caching features.
No website owner should have to use Disqus with its slow loading and third party servers. The only viable excuse for Disqus I can see is if you don't want to pay for decent hosting. By offloading commenting you can reduce load. But with Thoughtful Comments, we reduce the load of comment enormously via caching. We'd still love to see our comment caching technology added to WordPress core, improving sites around the world and reducing WordPress publishers' dependence on third party software.