I'm deciding between Rivendell Grip Kings, Velo Orange Sabots, and the Rivendell Thin Gripsters:

Review of the VO Sabots with mention of the Grip Kings:
Review: Velo-Orange Sabot Pedal ? A Pedal Revolution? @ The Path Less Pedaled

Short comparison of the Sabots vs. Thin Gripsters (mostly just photos):
Spotted: Velo-Orange Sabot Pedal vs. Thin Gripster

The reviewer says that his foot slipped off the Sabots a couple of times under wet conditions but the pins can be replaced with sharper ones if needed.