What are the Pros/Cons of Exchange Resource forest and Account forest Topology?

Hello,

We are planning to deploy exchange server in resource forest and account forest topology where user accounts will be in one AD forest and Exchange Mailboxes in other AD forest.

1) What are pro and cons of these kind of deployments?

2) Does GAL, Auto discovery, Active Sync, Outlook Anywhere and other features works properly?

3)Which are the features are not supported in this kind of deployment?

3) Is there any options other than using Linked Mailboxes?

Thanks

Ajath