I don't know abt the Daddy O but I've used the SD-2 and it ROCKS.
It can do a mild breaking up tone... to a nice light crunch. Turn it on to Lead mode and you can get smooth FAT light overdrive to something nearing heavy metal. Throw a booster before it and you get heavy heavy metal.
I've recorded a track with it... its on the thread called X2N Review or something...
Hehe... but its a discontinued product... all the best to finding it!