Features & Benefits can be as it says, where you can list the features and the benefits of a product. Or it could be used as Pros and Cons where you could list the good and the bad. You can have upto 5 each.
You can add a header to each list to be displayed or you can leave them blank.
To add Features & Benefits to a Review Type make sure to check the Features checkbox when creating a Review Type.
If you have already created the Review Type then you can add the Features by Updating that Review Type.