I have moved my iPhone back and forth between two different Macs several times without losing anything.I did not use the Restore, I simply copied my entire ITunes folder from one Mac to the other and ran a sync. I get a message that the phone is synced to another computer so I tell it to sync to the new one.
Then I have to go into iTunes and tell it to sync all the local data (Address Book, Calendar, etc).
If you have a disaster, you can restore the PC to the state it was in before you attempted the transfer.
Bebides there is a step by step instruction on
How to transfer or backup iPhone contents to Mac.Hope it can do you a favor.
Note:
The contacts should be in the Address Book app on your Mac