I don't have any of those problems - I don't have people going overseas, but I have good coverage. For actual changes to info, HR keeps their own database, I simply run a script to reflect those changes to AD.
It's also the business too - most of the people with BBs are actually communicating with the same handful of people internally, or a bunch of different people externally (which they use contacts for).
I don't know what you mean about no emails to admins... you can block that in exchange.
As for Caller ID - well I just make the tel provider turn on the called name display
So yeah - I still don't get why that's less work - I run a script to update the HR database to the AD, force a rebuild of the OAB (and I don't even do that most of the time). Your way makes it sound like you spend all day helping people resyncing.