Dunno about a write up, but out of the ashes of AI Dungeon, NovelAI was born. The model isn’t as good as GPT-3, but the UI and options are better, and unlike AI Dungeon, the company never reads your stories; they can’t, because they’re encrypted, and by default they aren’t even stored in the cloud IIRC.
https://novelai.net/#/
https://www.reddit.com/r/NovelAi/