I was there last week and mostly the bus service was great. I was at POFQ, so we were picked up and dropped off first when the busses stopped at both resorts. If I remember, every park except Magic Kingdom shared the busses, but even occassionally the Magic Kingdom bus stopped at both resorts. Must just depend on the day and crowd, I guess.
On a related note, we had the coolest bus driver on Saturday night. I think his name was Jeff (?). He entertained us with Disney trivia and songs on our trip back to POFQ from the Magic Kingdom.