I own the P70, and from what I can gather online the Amici 750 has roughly the same diameter cooking floor and the same dome height. The insulation looks relatively the same as well. I am not sure what the materials are for the Amici dome. And none of the Amici literature says how high a temperature the oven is rated for, or how high it will go. Those are the questions I would ask of CBO.
It looks like the P70 now can come with it's own stand. So if you go that route, the P70 will be cheaper. But if the CBO can get up to Neapolitan temps, i.e., 850 on the floor, then it looks like you will be able to get the same performance from either one.