We were VIP disembark on the Dream in June. It goes pretty smoothly. They have you meet in the aft lounge until they are ready to do the VIP disembark. How are you getting to the airport? Carnival transport? Taxi?
Self assist will be faster (I think) You may save time since you have your luggage with you. Even though we were VIP, our luggage took forever to come out. So it would be safer to do self assist.
To add to what Linda said above abut VIP not getting you through customs faster, we have found that if you get a porter to cart your luggage for you they can get through customs faster (they normally have a porter only customs line.) So depending on the time you actually get off the ship, consider that if you are running behind.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013