Many of our clients don't like the paged comments feature of WordPress as they like to have all the keywords occurring in the comments present on our article page and not spread across multiple pages. Keeping thousands of fresh comments on the page with every possible combination of keywords helps them rank at the top of Google for very competitive product categories.
Our front-end comment moderation plugin Thoughtful Comments includes comment caching feature, this article describes why that is important even if you are caching your site HTML: Improve your WordPress speed by Caching Comments.
However the downside is that it doesn't work for administrators and that the cache has to be purged and rebuilt when comments are added or removed. It's also usually slows down logged in users as we move more and more of our clients over to a membership or at least logged in user model.