I can only comment for UK pages. One thing I know is that Google's data source is very important, you need to know the format of the listing they are looking to match if you want your site (even if it's the official site) to be associated with the listing. The UK data has changed from Yell to a Thomson Local dump (which will now start to diverge from the Thomson Data as Google collect their own data and clean their database via a third party).
My main area of interest in how sites rank for 'web pages', it seems that pages with a title that includes the business name are doing well. It seems to be an attempt to be less reliant on pages that simply list the company amongst many others.
Location is very important in the UK still, an arbitary postcode has been chosen for the center of each place name and if you are closest to it then you are in luck.
My gut feeling is that Google and others know that this is not enough and players will strive to get 'deeper' information (opening times, areas covered etc) so that people make less failed contacts (good for businesses and consumers). Collecting that info is a huge task and even Google will struggle (hence the recent incentive scheme for people to add local listings).
I can only comment upon the states. I speak fairly regularly w/ Bill Slawski who has published regularly on patent items including a significant # of issues that impact local and G Maps. I also speak fairly regularly w/ Mike Blumenthal who has commented upon google maps in his blog....blumenthals.com/blog.
I've been following this for sometime.
Unfortunately I don't see enough commentary on the logic of g maps and my testing is pretty limited to a few topics.
I'd rather not generalize on that limited testing basis.
Nevertheless there were changes in the states for various rankings w/in G maps as of 8/9. I was just wondering what others saw and their impressions of the changes.
As for me, I generally saw a more logical ranking...though I couldn't put my finger on what aspects/what weights Google placed on information to rearrange the rankings I saw.