There is a difference between a dome and a vault. It's their efficiency. A dome is more efficient for baking pizza while the vault is more efficient in baking breads. But that doesn't mean that you cannot bake pizza in a vault and you cannot bake a bread in a dome. It is just those two ovens has their own specialty in making a better job in baking.
Both ovens bake just fine if you properly built and insulated it. The advantage of a higher mass oven is that it will retain the heat for days without refiring, and that retained heat can be use in baking pan breads,pastries and slow cooked meats. The choice really comes on what you will be making the most: a pizza or a bread.