Honest verdict
Nano Banana is strong, but not for the same reason as Rendervi.
Nano Banana is impressive for speed, blending references, and low-cost experimentation. If you are a technical team building your own workflows, it can be a strong image engine. But if you need a product that helps architects keep outputs precise across real project views, Rendervi is the better fit because the workflow is already shaped around architecture instead of around generic image prompting.