Bought a BGE, complete with pizza stone and BBQ Guru. Was able to get that sucker up to 850 with little problem. The issue was that I was running through some serious charcoal and hight temp gaskets. The top of the pizzas looked like they came out of a home oven. The bottoms of the pies looked nice. I kept it because I can barbecue year round using very little fuel.
Built a 42" Pompei style oven. It works beautifully, except that it takes about a banana box full of very dry wood and 3 hours to get it up around 850. This isn't really a problem on the weekend, but when you just want to experiment a 1 or 2 pies it's a pain in the ass. Having really dry wood is a problem if you start to run out, simply because others have a different idea of what "dry" is. I now use this for larger parties at my house. There is nothing like hanging out on the patio at night with the fire crackling, people laughing, and popping out fresh pies.
Bought a 2 Stone. I now eat pizza whenever I want. I fire up the oven and in 20-30 minutes I have roof and floor temperatures in the range of 850-900. I need to keep track of how long a bottle lasts but I seem to get about 4 hours out of a new bottle. $23 for a full bottle.
The 2 Stone is oppressively expensive, but the quality of construction is excellent. I don't know what your financial situation is, or even how much you plan to use it, but if you were looking for something affordable I would take a long look at the Blackstone. I have never used one, but I see a lot of awesome pies from the other members here.
Before you buy anything make sure you figure out how serious you are, how much time you can devote to heat up, what you're looking to spend, etc.
Hope this helps.