DALL-E 4 is the OpenAI image model - the path of least resistance if you're already in the OpenAI ecosystem. Quality is high, and the ChatGPT integration (edit, vary, ask-for-changes-in-natural-language) is genuinely useful.
The price ($0.08/image at 1024px) is twice Imagen's, which is the main reason it ranks #4 here despite excellent quality. If you're paying for ChatGPT Plus or have GPT-4 API access already, the convenience often outweighs the price gap.
Verdict: convenient default, not the best price-per-quality. 8.4/10.