We've all been bombarded by a gazillion AI writing tools. They all have their pros and cons and I'm not looking to pay more for less functionality so I decided to try a bunch of them so that you don't have to. Context: I like writing short stories and some non-fiction essays. I am reviewing with that perspective.

1. Sudowrite
   The UI for Sudowrite was clean and intuitive with a slick tutorial so we were off to a good start. I really liked the Story Bible feature and it helped me organize my ideas really well. I started experimenting and initially found some of the rephrases quite unhelpful. I started tweaking to see if there was anything I could change to get better results and before I knew it, I had burned through the word count on the free trial.
   I thought I would subscribe for a month and was taken aback that even the highest subscription tier had a strict word count. If you want an easy beginner tool for AI-assisted writing, you can check out Sudowrite but if you're going all in for NaNoWriMo an unlimited option would work way better.
   Good for: Beginners with AI-assisted writing, people willing to pay for convenience
   Rating: 6/10

2. Grammarly
   As the most well-known/mainstream writing aid, I had high expectations of Grammarly. It is priced at an accessible $12/month and the interface is familiar to users of the Grammarly plugin. On testing, I found that it didn't make significantly better improvements over GPT 3.5, the sentence rewrites were rather basic. Even paid users are limited to 1000 prompts/month which heavy users would run through quite fast.
   Overall, it seems better suited to copywriting and improving some written material than as a full-fledged editor.
   Good for: Essays, copywriting, short-to-medium length works
   Rating: 5/10

3. Quarkle
   Quarkle is a wildcard entrant to my comparison with some clear upsides and downsides. It had an unlimited use free tier which instantly reeled me in. The open-ended chat functionality was great and you can use it to brainstorm and re-write during the writing process. However, it was Quarkle's ability to critique/proofread text that really stood out to me. While not 100% perfect, the Google Doc-style comments brought solid feedback for the improvement of the actual story. When it pointed out a character’s actions were inconsistent with their motivations, it stood out from competitors.
   Despite the unlimited free tier, I was curious and did end up getting the paid version and the improvements were worth it for me. Not having to work around content restrictions on adult content while asking the AI for suggestions is also a clear plus.
   It did have its bugs though. During testing, the chat occasionally got stuck and refused to give new answers after long conversations. The only way I could resolve this was by hitting delete chat. The site seems to be actively under improvement though so hopefully the devs resolve that soon.
   Good for: Editing your work/ Free, unlimited open-ended writing
   Rating: 8/10

4. Rytr
   The first thing I noticed about Rytr was how geared it was for more commercial writing applications. The abundance of templates makes the process of content creation more streamlined and it was useful to be able to guide the tone of writing with the click of a button. Where it falls short though is riffing off what you've already written and working in line with that style. This, along with the stilted sentences makes it less-than-ideal for creative writing.
   I was excited to try out the magic command function where you give it specific instructions on what you want it to write and the AI writer does so but I quickly realized that while it nailed the style/format, the output was confusing at times and outright contradictory at others.
   Overall, it can be an economical option for writing marketing and SEO materials but I would definitely fact-check and proofread before hitting publish.
   Good for: Marketing and content creation
   Rating: 6/10

5. Novelcrafter
   Novecrafter was on one hand really intuitive with the UI and on the other really unintuitive with the AI bits. There was a lot of technical jargon I wasn't familiar with: Temperature, Top P, Frequency, API Keys. But after that steep learning curve, things started to get more interesting. The codex is great for organizing the big picture ideas and once I got the hang of things I found an appreciation for the customizability. On the other hand, the customizability could also be very alienating for people who just want to write and not learn a whole new software.
   Overall, I did feel this was the best solution for mass writing AI-content for novels. I really liked how easy it was to storyboard and organize the plot. Due to the organization, the AI picks up a lot of information automatically and writes long passages coherently. On the downside, I didn't like having to purchase both an API key and as well as a subscription (in the future). A paid subscription should include the cost of the words.
   Good for: Organizing ideas and storylines together
   Rating: 7/10

I’ve been testing a bunch of AI writing tools over the last year — mostly for long-form writing like novels, nonfiction books, guides, and self-published Kindle projects.

A lot of people ask: “Which AI tool is best for writing a full book?”

Truth is… it depends on your writing style.

Some tools are great for brainstorming, others for expanding chapters, and a few are actually usable for full book workflows.

Here’s a breakdown of 20 AI writing tools that are genuinely useful for writers.

No hype. No “this one tool can magically write your whole book.”
Just practical info.

📚 1. Aivolut Books

Best for: structured book creation
Perfect for people who want chapter frameworks, consistent tone, and a real book workflow (ideate → outline → draft → revise).

✍️ 2. WordHero

Best for: short-form + chapter expansion
Great templates and fast generation. Good for writers who outline in another tool then expand with WordHero.

📖 3. Sudowrite

Best for: fiction
Phenomenal at world-building, character emotions, and visual writing.

🧠 4. ChatGPT (Free or Paid)

Best for: brainstorming and editing
Not book-specific, but extremely flexible.

📘 5. Writesonic

Best for: nonfiction + blogs
Useful for writers making instructional or educational books.

⚡ 6. Claude.ai

Best for: polishing + rewriting
Very clean, coherent paragraphs. Great rewriting tool.

📝 7. NovelAI

Best for: fantasy and anime-style stories
Not ideal for nonfiction, but great for fiction inspiration.

📚 8. Jasper

Best for: marketing-heavy book writers
Strong SEO and content marketing angle.

📂 9. Notion AI

Best for: note-taking and book planning
Not a book generator, but great for organizing.

📄 10. Scrivener + any LLM

Best for: writers who want full control
Scrivener stays undefeated for long-form structure.

🪄 11. QuillBot

Best for: rewriting + clarity
Good for polishing chapters.

🌐 12. Google NotebookLM

Best for: nonfiction research
Amazing for summarizing and reorganizing sources.

💬 13. Rytr

Best for: quick drafts
Simple tool that works for fast idea generation.

📚 14. LibreOffice + local LLMs

Best for: totally free writing
Manual but powerful combo.

🎭 15. Character.AI

Best for: dialogue
Helps with conversations and character development.

✏️ 16. Ink for All

Best for: SEO book writers
Useful for keyword-based nonfiction.

📜 17. Hemingway Editor

Best for: simplifying writing
Great final editing tool.

✨ 18. Grammarly

Best for: grammar + clarity
Still essential for editing.

🔥 19. NovelCrafter

Best for: storyboarding fiction
Good for planning complex plots.

📘 20. Reedsy Book Editor

Best for: formatting
Not AI, but perfect for preparing your final manuscript.

So which one is “best”?

Depends on what you're writing:

For fiction:

• Sudowrite

• NovelAI

• Character.AI

• NovelCrafter

For nonfiction:

• Aivolut Books

• WordHero

• NotebookLM

• Writesonic

For editing:

• Claude

• Grammarly

• Hemingway

For idea generation:

• ChatGPT

• WordHero

• NotebookLM

There’s no one perfect tool — but combining 2–3 usually gives the best results.