Relevanssi Premium 1.10.5.1 fixes a nasty bug caused by an invisible character in a place where a space should be. I quite dislike those invisible characters…
Download from the download page or auto-update.
How to display relevancy score
Relevanssi stores the relevance score it uses to sort results in the $post variable. Just add something like <?php echo “Score: $post->relevance_score”; ?> to your search results template to display the relevance score….