We only took the bus to/from the Magic Kingdom and Animal Kingdom when we were there last May.
We had a tough morning going to the Magic Kingdom at opening, and about 3 buses went by already full, or close to full so that only 1 or 2 families could board when it made it to the Beach Club - that was the reason for my posting that buses were frequently full. It was a frustrating morning.
But I will echo goofy4tink's sentiment - we really had a great stay at the Beach Club, and I found the bus to be the only negative aspect of our trip there. Would I avoid staying there again because of it? No way!