I've had mixed success with them.
Hammared the bass on them trolling on the French last year, but no pickerel.
Caught a bunch of pickerel on them last year on G-Bay.
But last time I went out, I got seriously out fished by a guy using a worm harness. Later in the morning, the guy got snagged up, and lost a hook on the worm harness, so he tied on the slow death hook to the worm harness and kept catching fish.
The speed is very important, and the placement of the worm to get it to "twirl" just right. I generally have to use a GPS showing my speed to maximize my sucess. Different speed for different conditions. Usually between 1 to 1.5 km/h.
I use it behind a slip sinker, with 4 to 5 feet of flouro leader for 5 to 20' range. And about 5 to 6' of flouro behind a yellow and orange bottom bouncer for anything deeper.
Might be a fluke, but I prefer the red hook.