Dumb question:

Coming from ZFD (where you could really only do "local" GPO), why would I want to use AD GPO in ZCM?

I mean if I have a GPO in AD already, why not just use that?

Are there some features missing in a local GPO vs. AD GPO? (In our case, workstations are Windows XP only at this point and we don't use ZEN for GPO for SERVERS--just XP workstations).

The only reason I can think of is maybe if you were more familiar with the AD stuff and you made an AD GPO but didn't apply it (not even sure if you can do that?) and you wanted ZCM to deploy it (like you didn't have AD DC in your regional offices?)