One new feature that comes with FB integration, the persons FB Jabber address is now in contacts as "instant messaging" (i.e,
userx@chat.facebook.com). I see apple allowing Messages app to IM FB users in the future. Just like the messages app on the Mac. If this expanded to Yahoo I would have no reason to use BeeJive anymore.
Now that I think of it, Skype integration would have been kick ass on the iPhone... wishful thinking.
Also regarding FB integration, FB calendar is now synced with Calendar. You get birthdays and events. If they allow you to post directly to a persons Timeline via Contacts, then Occasions app will be redundant. Right now with Occasions, you can send a person birthday wishes on their timeline directly from the app. Apple should incorporate this as well. I do like being able to see FB birthdays in Notification Center.
One thing I dont like about FB integration, you dont get a full screen contact photo, only the small thumbnail when a person calls. But on the plus side, it does sync when a person changes their FB photo. Nice.
With over 600 FB friends/associates, and over 200 contacts, I did end up with a lot of dups in contacts. However, those where the names matched exactly became linked cards. You also have the ability to Link those that dont automatically match.
Overall, I'm liking the FB integration, I'm not a big FB user but a user none the less. Looking forward to things to come.