On my mountain bike, I can see the difference between tires due to thread and width. Some are faster rolling tires, some with corner better and some will shed muck easier.

On my road bike, the tire is a slick. There is no thread to say "this tire will be faster," or "this tire will allow me to get the bike down on a fast turn."

I know its likely just my ignorance, but how does 1 slick differ from another? What make a tire worth $30 opposed to $50?

Also, what is the consensus on tubeless set-ups on road tires? On my mountain bike, I am running a ghetto set-up and had INCREDIBLE success with it (only flat was from a twig literally ripping off the valve stem at the screw). One of the great parts of running tubeless on a mountain bike is to decrease the air pressure with less risk of pinch flats.