I'm working on a local wordpress for test before running the plugin on the live site but to give you examples:
1- I took a large article about one subject and divided it into 4 posts, the 4 posts are very similar in content. On viewing each post, other posts that are less related appears before the really related ones.
2- I added an Arabic post (BTW does your plugin support Arabic?). Anyway, when viewing this lonely Arabic post on the site, English posts that are not related at all to it appear in the related posts. Note: I added the Arabic post in a different category so the other posts that appeared are not related to it even in category.
I think that the tags which are generated from the title & text should weigh more than 2, it's more important that category.
I hope to get a reply for the Arabic part & hope for continuous enhancements because it's really a good plugin.