Earlier quoted context omitted.
Nobody is able to use Parti or eDiff. Compared to models you can use, the experimental Dall-e or Bing Image Creator is second only to midjourney in my experience.
I haven't tried those two, but I'd be surprised if they were better than Stable Diffusion. Which is free, runnable (and trainable!) locally, and already has a large ecosystem of frontends, tweaks and customized models.
I would still easily put both ahead of the base models. You won't match the quality of those models without finetuning. When you do fine-tune, it'll be for a particular aesthetic and you won't match them in terms of prompt understanding and adherence.