WordPress directory authentication plugin through LDAP and LDAPS (SSL).
Using 4.1.1, works flawlessly, very easy to set up.
Could strongly use LDAP group/WP role mapping. Unless I missed it, it would be wise to add this. LDAP group users are likely going to fall under a different role than the WP default (subscribers)
Hardly a true con. Plugin works great, highly recommend.
I've got this installed on a few sites, and a couple multisite installations, and it saves me so much time! Works well with our campus LDAP setup.