I've used both Pinhead (when it was marketed by Kryptonite) and Pitlock locking skewers/seatpost binders. I find the Pitlock to be much higher quality.

The Pitlock is easier to use, (the Pinhead "key" is a PITA. I wouldn't want to be sitting by the side of the road in the rain trying to use one), better designed, and made of higher quality steel. My Pinheads' rusted. My Pitlocks didn't.

http://www.pitlock.de/en/