I've got to vote to go with one with a spring as well. I used one without a spring and sometimes the valve would get stuck and not shut off when bottling. It happened 3 times with a 5-gallon batch and I probably lost a full bottle of beer that day. That was the last time using a non-spring one.
Both leak a little, and by leak, I mean a few drips between bottles. If you're getting more than that, something is definitely wrong.
The comment about bottling over the dishwasher was also a good one, I used to do it over a bowl, but the dishwasher is easier on cleanup.