John, I like the cog system pretty well. I've rigged 4 or 5 models with it so far, and it takes me around 4 or 5 evenings to rig a character. I tend to take my time, though...
I like the way the joints deform. They don't look like rubber hoses, anyway... The way the torso is set up lets you control it with a main back control bone, which works well.
The main problem I have is figuring out where to put the bones in the knuckles at the base of the fingers.
I didn't know a thing about rigging, so the tutorial helped me learn how the most common constraints are used. I'd like to learn more about the other types of constraints (especially the dynamic constraint).
Also, I haven't tried using it with the Setup Machine. Maybe some of the others here have used them together, or you could ask the Anzovins.
HTH!