We are going to be migrating to Exchange 2007 in the next month or so.
We have an existing 2000 AD with Exchange 2003 in it.
We have a new 2003 R2 AD that will have Exchange 2007.
My question is... with about 300 desktops and 35 servers in the 2000 AD which route would be better:
A)Installing 2007 into the 2000 AD, thus same forest, same org, makes moving mailboxes a bit easier, then once everybody/everything is migrated over, then either renaming the 2000 AD (obviously by getting some 2003 DCs in and demoting the 2000 DCs) to the 2003 R2s domain name
B)Keeping the new 2003 R2 domain, and doing cross-forest moves (which I understand is only possible via Exchange Command Shell currently) I imagine this is the cleaner route, but I'm a little hesitant about the possible gotchas/hiccups that may surface via this route.
Which solution would you recommend, and why? Does anyone have any experience with either scenario?