Better WP Security is a great plugin. There are a couple small issues I struggled with, which I will mention here as a bugfix request and to help others. I'm new to WordPress, so please let me know if there is a better place to post bugfix requests. So 4/5 stars so far, will revise that up when the bugs are fixed:
1. After renaming the database prefix, user roles in sub-sites no longer work. Fix: option name "wp_[blog ID]_user_roles" needs to be updated as the database prefix changes. It should read "[new datebase prefix]_[blog ID]_user_roles". It appears BWPS does this for the main blog but not for sub-blogs. Thanks go to this discussion: http://wordpress.stackexchange.com/questions/11725/help-why-my-roles-are-not-showing-multi-site-network
2. This isn't really a problem, rather cosmetic: After the admin user is renamed, the "A user with id 1 still exists." notice remains in red. Following the link I am told there is nothing further I can do. Is this a bug or is there something I don't know about "user with id 1"?