Follow up to the OP, I have the UG and it confuses me because it compares driving yourself and taking the bus, and I would assume the bus would be quicker, but it says driving is a little faster????
That depends on a lot of factors.
For MK, the bus is usually a little quicker, sometimes a lot quicker, because it drops you off close to the park gates, while the parking lot is on the other side of the Seven Seas Lagoon. Even if you get there early enough to snag a parking spot withing easy walking distance of the TTC, you still have to board the monorail or ferry and ride accross. If everything goes perfectly (i.e. you park close to TTC, walk right onto the monorail, and the doors shut right after you board), you will still have an extra 5-10 minutes travel time before arriving at the gates.
So driving to MK from AKL, best case would be 15 minutes plus 5-7 minutes transportation accross Seven Seas Lagoon, whereas best case for a bus (i.e. you walk onto the bus ust before the doors close and it leaves AKL) would only be about 15 minutes.
For the other parks, driving is almost always faster, because there is no addition ride accross a lagoon at te other parks.
But I drive to MK anyway. If yuo take the bus, you don't need to ride the monorail or ferryboat - and I really love riding the monorail and the ferryboat! To me, they are attractions as much as Pirates or Haunted Mansion, so as far as I am concerned, my park experience begins at the TTC, not at the park gates. YMMV.