In essence, they have modularised their product so separate out the SSO functionality from the authentication functionality with a simple upgrade to incorporate both components. With ENA, you can now add strong authentication through a variety of methods to the windows login. Where this gains advantage over other strong authentication suppliers, is the ability to have different authentications under different scenarios.
There seems to be a wide range of authentication types supported including tokens, cards and biometrics.
This should tie in nicely with their up and coming product in the summer which ties physical and logical access together.