Very similar to what John L Scott did (they were both done by the same dev company) but a little more localized as far as neighborhood drill-down. They also added sold property listings driven by address reference rather than map based, but still pretty handy.
As I’m an agent for Coldwell Banker Bain I’ll refrain from singing my praises of the improvements. I’m a little more interested in what everyone else thinks of it. Check it out at http://www.cbba.com/InteractiveMapSearch.aspx