Flux vs Midjourney for product mockups — and how I stopped maintaining two workflows

I generate a lot of product mockups. For a while I used Midjourney for the “hero” hero shots and a Flux setup for anything I needed programmatically in a batch. Two totally different workflows: one interactive, one API. Keeping them in sync was annoying.
I’ve since routed both through one gateway so I can hit Flux and Midjourney from the same script with the same key. Practically, that means my batch job can generate a Flux draft, and when a client picks a winner I regenerate a polished version through the other model without leaving the pipeline. The consistency of having one request format across image models is underrated.
My honest take after a few weeks: Flux is my default for iteration speed and programmatic control; I reach for Midjourney when I want a specific aesthetic that’s hard to prompt elsewhere. Neither “wins” outright — they’re different tools.

Question for the room: how do you handle brand consistency across image models? I’m building a little prompt-library so the same product reads consistently regardless of which model rendered it, but I’d love proven approaches.