The rate of change in Google Maps has been a topic of discussion. I noted issues with reviews not being updated in almost a year for certain businesses.
Matt McGee has a very good piece reviewing his experience. His conclusion: the slow rate of change of these prime listings is great news for the businesses that are fortunate enough to score one of those A, B, or C spots. And until the data gets processed more quickly, good luck to those businesses on the outside looking in.