Google Map API V3 vs V2

Adding Marker in V2:
map.addOverlay(marker);

Adding Marker in V3:
marker = new google.maps.Marker( { position: point, icon: icon1, title: sTitle, map: map } ) ;

Removing Marker in V2:
map.removeOverlay(marker);

Removing Marker in V3:
marker.setMap(null);

Actually there are many more difference, but this post only highlighted basic one.