They're just called "Pizza" stones, but really they're baking stones. The ceramic cooking surface gives a very very uniform, even heat and retains it's heat well (So the pizza stays hot on the table). Crust comes out tender-flaky perfect and it's hard to burn it.
The problem is those dang Costco Pizzas, they don't even fit in my oven!
Oh yeah, Costco's pizzas are good. You can either buy them cooked up front, or uncooked back in the deli. You get a HUGE Pizza for $8. It doesn't look that big in Costco, but that's because everything there is big. I'm not joking when I say it won't fit in my oven. Edge of the pizza touches the edge of the back wall of the oven /ubbthreads/images/graemlins/icon15.gif