My experience in May was terrific. The wait for a bus was minimal (average of less than 5 mins.) for any park. We had a car, but it was basically for going to other resorts for meals or to visit DTD. The bus service to/from DTD is not so good -- JMO.
We loved the boat shuttle to/from MK! That was the best way to travel.
Overall, I give WL transport to the parks a big thumbs up. Note: several buses to the parks were shared with FW. Not a big delay getting to the parks.