I'm after some advice as to which of the two SAMBA/CIFS file-system options for OES2 is preferable when the primary user source is being migrated to Active Directory.

The customer has a substantial eDirectory Tree (Education related) which spans multiple sites and has a large number of user accounts and groups (tens of thousands of users, thousands of groups).

We have been systematically upgrading their Netware servers and NCS cluster to OES2 servers (we have covered approx 50% of the sites).

They now have decided that they want to use Microsoft Active directory for their primary user source (they have IDM synchronization of accounts between eDirectory and AD so the same user names and password exist in both systems). Their "long term" plan is to remove all of Novell products and "rip and replace" with Windows servers.

Their initial target is to replace the remaining NetWare servers and NCS clusters with windows servers, with the OES2 (linux) server to be retained for some time. (if I can show the advantages of OES2 they may be retained forever).

My question:
Since OES2 supports both CIFS and SAMBA file-servers (only one or the other). Which is the best option to deploy.

If possible we would like to leave the same volumes and filesystems intact and make them available to "client-less" windows 7 workstations, just using AD based user login credentials.
If possible we would like to use the existing NSS trustees to manage file access rights. It would be a substantial job re-applying MS ACL's to all of the file-systems and would then diminish the advantage of retaining the existing OES2 servers. (The IDM synchronization of eDirectory accounts will be maintained so eDirectory credentials could be used).

What are the advantage/disadvantage of CIFS Vs SAMBA on the OES2 servers and which would most closely match these requuriements?

All responses appreciated, feedback from people with "coal face" experience most useful.