In reply to Keith Davis.

We'll be keeping it. We already use Jetpack for so many other aspects of the site, Related Posts is a big bonus. I like the fact that the layout of the related posts is similar to what is used on much larger, content heavy sites. It's also nice that the WordPress.com infrastructure is handling all the processing to find out what is related instead of our hosting account.

If there is anyway you could offload the relationship processing to a service, I think it's something you should look into.