I use Pampered Chef Family Heritage Stoneware Classic Round Stone mostly to cook pizza, and it works great for this purpose. Since the stone is evenly heated, the pizza never burns, it turns out just right and thoroughly cooked. All kinds of other dishes can be baked on this stone: pies, chicken, cookies, potatoes - basically anything that is not runny, as the stone has no rim.
The stone is made of clay and it can break if dropped. Sudden and drastic temperature change can cause breakage as well (for example, if you place frozen food on it and then stick it into the oven). You also need to be very careful when you take the stone out of the oven as it will be *very* hot. I usually put it on top of the stove and let it sit there and cool off for a while.
The stone requires some special care. It should not be washed with soap as soap will penetrate it and affect the taste of dishes you cook on it later. I wash my stone with water and scrub it with the special nylon scraper that came with it. The stone darkens with time, which is normal.