I totally see the benefits of JSON, pull over a lightweight array of data to stuff into my Google Maps (and template through to show a list of the points as well). I've heard a lot of talk about KML.
Which is the preferable way to pull points into Google Maps, JSON || KML? My primary concern is performance, but also breadth of features that could potentially improve the map.
Personally I use json because the kml resulting features are less flexible than the features that you create from parsing json. For example, you can't add a hover event to a polygon from kml.