Adding events to multiple markers in a Google map
Your code is definitely simpler, though I would not use it myself. There is no good reason to have an anonymous function, and if you have multiple markers, then you will have multiple clones of the same function. I would create a named function and use that function with addListener.

(I am assuming that infowindow is available to this function)

function setPositionAsContent(){
  infoWindow.setContent(this.position.toString());
  infoWindow.open(this.map, this);
}

google.maps.event.addListener(marker, "click", setPositionAsContent);