Fire brick is very hard to find and extremely expensive in S Florida. It was actually cheaper to buy the kit than to try to buy the materials individually for us. Also, another factor was code and distance requirements from house/property line where we lived, and we didn't really want to put it where code compliance would have required (obviously RD doesn't have that issue). Plus, we were considering downsizing so that meant we'd either have to make it portable or have it and use it for a year or 2 and then take a loss on the money spent to build it.
Craig started looking at the Big Green Egg after we decided to pass. The BGE can get super hot and does a pretty good job and stays at temp for a long time as long as you don't open it too much, which is good for bread baking and roasting, not so much pizza.
The Weber with the pizza attachment, especially since Kettle Pizza came out with the new modification on their original that makes it easier and safer to add coals, does a great job cooking pizza and even bread. With the Kettle Pizza insert, you can make a double layer by putting the regular Weber grill on top of the insert. Only thing is, it gets really hot up top when the dome is on so you kind of have to wait until you are close to end of cooking on the bottom to start bread up top or it gets a bit too brown and/or burned on the top.
We use seasoned wood when we are cooking pizza or bread.
Just a couple of alternatives in case you want them.