I'm quite happy with the tool. 👍 It takes 12-24 hours to write a 50.000 words book. The UI is very simple and intuitive, the results are fine for the most part. I like that the steps are clearly labeled.

However, it can be better in a few ways:
📑 I find the TOC implementation to be too stressful. It never aderhers to my prompt, it crafts mediocre tables, and later I can add only 1 chapter and 2 parts extra – that's it. I would like to distruibuite the content structure in a more personalized and refined way. I like the new custom JSON, but has the same limitations. I would like to set more sections, parts, and suggest talking points for each.
🗣️ I seem to never find a good style prompt. Youbooks tends to write very sophisticated. Maybe too much (at least in Italian). If I'm writing a short and simple lead magnet, and I specify casual, conversational, etc. it won't care and it tends to output the psychology manual.

👉 In short, TOC feature is too limited and writing styles aderhance can be improved.

The output is very usable. You can get a very good draft for later revision with another AI tool (I tend to use ChatGPT or Claude Code) and/or manual edits. As I said, Youbook output is always too linguistically sophisticated for my liking – the same prompt on GPT gives better results.