Go shopping for a new pizza stone, and you'll find a huge variety of surfaces, from metal to clay to natural stone to man-made composites. If you were going solely by recommendations from respected testers, you might settle on the baking stone sold by King Arthur Flour.
The King Arthur Flour catalog quotes a review from Cook's Illustrated:
We tested 10 baking stones and came to prefer a fairly large one (16 by 14 inches is ideal) with smooth edges. The Baker's Catalogue Baking Stone's moderate weight and ample size make it our favorite.
The stone is a yellowish beige color, with a slightly mottled appearance and a smooth surface. It weighs 10 lbs. 4 3/4 ounces and stands 1 inch high. The stone itself is 1/2 inch thick, but it has feet and a thicker center section. The price is $54.95.
As with every other stone, I set the oven to 550 degrees and checked the temperature of the stone at 45 minutes into the preheat (527 degrees) and one hour (549 degrees).
Time for pizza! After 8 minutes of baking, the pizza was nicely browned on the bottom, with a very crisp crust. The top was well-cooked as well.
The results from this stone were similar to what I got with the quarry tiles. The crust was just slightly crisper, and more mottled brown with slightly darker and lighter spots.
Despite the similarity in the overall result, this stone had several advantages over the quarry tiles. First, it's made for food use, so there's no need to worry about lead and health issues.
Second, it's one piece, so there's no moving, shifting or adjusting. It goes into the oven and it stays in place. At first, I thought the legs were a little silly. Why not make it flat? But then I realized the the legs made it easier to grab the stone and get it in and out of the oven.
The downside: buying a dedicated baking stone is more expensive than buying quarry tiles. But in my mind, it's worth the expense. A well-treated stone will last a long time, and over the course of its life, you won't be cursing about the quarry tiles shifting around in the oven.