RfN is not integrated with Active Directory. It is designed to work on any Network Operating System and works in conjunction with policies, Zenworks, Active directory Group Policy Objects (GPOs) and other standard network security.
RfN's security is designed to fill the weaknesses left by Window's Group Policy Objects (GPOs) in a backward compatible easily administrable package.
Active directory is fine, but is not backward compatible with 9x machines, any security you want is reliant on the old systems policies.
Basically, active directory is very "corporate", it will protect machines from people changing wallpapers, cursory fiddling etc. If people are happy with this level of security then ok, use it. However, if you have tried policies (and GPOs) and have run up against its limitations, then that's where RfN comes in.
RfN's security is designed to complement any policy based system - not replace it. This is why we have a policy implementation built into RfN. Policies alone however, don't cater for determined hackers who edit shortcuts, rename executables use UNC paths, use web browsers, word, VB etc to exploit the numerous back doors within Windows.
RfN is also more flexible, with foolproof application banning, title checking to stop individual dialogs, path limitations to allow safe use of floppies, time limitations etc... plus everything users do is reported back to the server and logged to aid system management.
RfN is far more than just security, the network management and control features are far more extensive than Windows 2000 or other security products. Take the real time network views, remote control, status logs, graphs etc in LAN RfN...
Another example of RfN's flexibility - if you want to reset the passwords on a whole year group in one go, you can't with Windows 2000. RfN Account Manager includes simple wizards for modifying user accounts in bulk - giving you useful functionality over and above active directory. The only area where RfN could be integrated with AD but isn't (at the moment) is account management through RfN Account Manager. It creates and modifies accounts fine, but is not OU "aware". User accounts are created in the default "users" OU. If OU policies are used, then accounts can be moved via the usual Active Directory Users and Computers MMC.
In summary, Active Directory and GPOs are great and are free with Windows. (you don't even need third party applications to use GPOs). Use them, but when you find system's still being compromised or need more flexibility then look at the additional security and management tools RfN offers...