The only difference is that you can now set the cookie prefix name from the admin area. In version 9 it was hard coded as wwf9.
In version 10 this maybe different, which in some rare cases can cause issues. For those that experience cookie problems they should clear out their cookie cache.
The other difference is if you enable EU Cookie Directive Compliance. If you do then cookies are only set on the visitors browsers after logging in to the forum. For those that do not login only a temporary session cookie is set.