I bought the CST Czar tires to replace the original tires for my road bike. The route to my office is notoriously bad on tires - pot holes, rocks, sticks, you name it. The original tires (I won't name the brand) didn't last 200 miles before the front tire popped on a rock. When I looked at the slick profile of the CST, It was hopeful that they would be fast yet still have some durability.
Now that I have ridden this pair for 750 miles, I am very happy with their performance. The tires are able to handle small rocks, cracks, and rough surfaces on my local Illinois roads. They seem to be able to handle my normal 40 mile route about as well as the more expensive tires that my friends ride. Given that I could buy three sets CST tires for the price of one set of more expensive tires, these are my choice for my training run on my road bike. I wouldn't use them for racing, as I would want to save every wheel gram I could possibly cut. But they definitely do the job for day-to-day rides.