Bottom line: rank a text-to-image API by prompt adherence and style control first, output resolution second, and treat upscale as an optional export step — OpenAI's images endpoint or Imagen on Vertex AI when the creative carries a lot of legible copy, Replicate or Amazon Bedrock when you want seeds and swappable checkpoints, and a multi-vendor gateway when you'd rather hold one account than four for a single marketing app that has to ship posters and social ads on a schedule.
I'm a solo founder. Image generation isn't my product — it's the thing that has to stop eating my week so I can get back to the product. So I compare these on time-to-usable-file and on what the invoice looks like at month end, not on gallery shots.
Here's what I check, roughly in the order I check it.
What actually decides whether a generated poster is usable
Three things wreck an ad creative, and model count isn't one of them.
