Morley Bad Horsie 2
Sweepable Q, optical circuit (no scratchy pot), spring-loaded action returns pedal to upper position - touch the pedal, it's on, lift off your foot, it's off. Great design, great company with great after sales.
Some will argue that you can't 'half toe' it*, during solos, etc., and this is true, but it functions perfectly well for those who don't need this feature. One less thing to worry about on stage.
*never thought about it, but I wonder if the spring action can be removed, allowing for 'half toed' usage.