Agree with the PP. Any resort can run into problems, but these are not the norm. You need to understand that Disney buses are not on dedicated service to specific resorts. They are sent out by a central dispatch. Any given bus may pick up at POR for a run to MK, then be sent to AKL for an Epcot run. POR might have a problem one day but be fine the rest of the week.
We've been staying onsite since the 70s, and I can count on the fingers of one hand the number of occasions we've had what I consider a problem with the buses. But we're pretty laid back and are rarely in a hurry on vacation. There ARE guests who just aren't bus people. The ones who get antsy if a bus isnt waiting for them when they arrive, or who pout if they don't get a seat at park open or close, when they are busiest. Those folks I point towards the nearest car rental agency.