The rocket oven that Anne's link is based on works very well, we have made quite a few pizzas with the design as well as other baked goods. You can build it with a high temp thermometer included so you can read it with the door closed. It gets up to cooking temps pretty quick, I think it was around 10-12 minutes to get in the 400-500F range (I forget which, other than we were timing it) and then another 5-10 minutes per pizza based on the thickness and minimizing how often we opened the door to check. Smaller diameter wood packed in can get the temps very high, but you also have to deal with more coals that aren't fully burned up when you are trying to cook at a really high temperature. If you keep it around 450F that's manageable from my experience running the oven two different times.
Compared to the standard cob oven I think the rocket oven has more ups than downs, in that it's faster to get to temp and use, it can be also be moved around and would be viable indoors with little smoke. The temp can go up and down more compared to cob and you have to feed it while baking. A cob oven takes a long time to get up to temp but then it's a steady heat and you can put in say bread and leave it be for longer periods. But while heating you have more smoke and it's massive. So neither is a slam dunk over the other to me, it depends on your needs.
The holy trinity of wholesomeness: Fred Rogers - be kind to others; Steve Irwin - be kind to animals; Bob Ross - be kind to yourself
For me the rocket oven works really well. Simply put it uses so little fuel to cook with it. It usually requires about 2 or 3 pieces of 2x4 that are 10" long to cook most things for 30 minutes. You also need kindling.
I do not know what the fuel requirements for cob ovens, however I know it is not the same.
We have pizza party's here where we cook 10 or so pizzas and it is shocking how little wood it requires.....