I'm the opposite of Jan- I leave my pull cord hanging- I don't have the best coordination to reach up and get it out of my collar and then turn my arm around and pull down, so I leave it hanging and when I get out I just reach behind and it's right there to pull down on. Plus, if it's hanging down and something brushes my arm during the swim I just assume it's that and not a snake or fish that just touched me.
Just try it both ways and see which way you like it. Which skinsuit did you get? Those are pretty cool looking...I've thought about getting one myself.