We stayed at Pop the last week of August 2006 during free dining. Pop does have their own bus. It isn't shared with any other resort. We never had long waits at all and there was only one day that we had to stand on the bus instead of sitting. Can't wait to go back!!!
Also, their bus stops are the farest from from all the parks. We never minded it during the beginning of the day, but it sure did seem like a long trek after touring the parks all day. Even with that, I would still stay there again.