Claude vs. GPT-4 vs. Gemini: Choosing the Right AI Model for Your Book
One of the first questions new Galleys users ask is: "Which AI model should I choose?" It's a fair question — we support models from three major providers (Anthropic, OpenAI, and Google), and the right choice depends on your manuscript, your priorities, and your budget.
Here's a practical, honest comparison based on what we've observed across thousands of manuscript analyses.
The Models at a Glance
Anthropic Claude — Available in three tiers:
- Claude Haiku: Fastest and cheapest. Best for quick iterations and shorter works.
- Claude Sonnet: The sweet spot. Strong analytical depth at moderate cost.
- Claude Opus: Deepest analysis. Available only to BYOK users. Best for literary fiction and complex narratives.
OpenAI GPT-4o: Strong general-purpose model. Good balance of speed, quality, and cost.
Google Gemini 2.5 Pro: Large context window. Particularly strong for very long manuscripts.
Analytical Depth
This is the most important dimension for editorial analysis: how deeply does the model engage with your manuscript's craft elements?
Claude Opus leads here. It catches nuanced issues — thematic contradictions, subtle character inconsistencies, narrative voice shifts — that other models sometimes miss. If you're writing literary fiction, complex multi-POV narratives, or anything where subtlety matters, Opus delivers the deepest feedback.
Claude Sonnet and GPT-4o are closely matched. Both catch major structural issues, character arc problems, and pacing concerns reliably. Sonnet tends to be slightly more precise in its issue descriptions; GPT-4o sometimes provides broader context around its suggestions.
Claude Haiku is best for straightforward analyses. It catches clear structural issues and major plot problems but may miss subtler craft issues. Think of it as a fast first pass rather than a deep dive.
Gemini 2.5 Pro has strong analytical capabilities, particularly for longer manuscripts where the large context window allows it to hold more of the text in memory simultaneously.
Context Window and Long Manuscripts
Context window size determines how much text the model can "see" at once. For manuscript analysis, this matters because understanding a chapter often requires context from earlier chapters.
Galleys handles this with a multi-pass architecture — building reference documents (character profiles, continuity trackers, plot maps) that carry context between chapters. This means all models can handle full-length novels effectively. But a larger context window still helps for individual chapter analysis.
Gemini 2.5 Pro has the largest effective context window, making it a strong choice for very long manuscripts (150,000+ words) where cross-chapter context is especially important.
Claude Sonnet and Opus have large context windows that handle most novels comfortably.
GPT-4o has a sufficient context window for standard novel-length analysis.
Speed
If you're iterating on revisions and want fast feedback:
Claude Haiku is the fastest option — analyses complete in a fraction of the time of other models. Ideal for quick checks during active revision.
GPT-4o and Claude Sonnet are moderate speed — expect 15–30 minutes for a full novel.
Claude Opus and Gemini 2.5 Pro are slower but more thorough. Best for deep-dive analyses when you're not in a hurry.
Cost
For credit-based users (not using BYOK):
| Model | Credits per Novel (~80k words) |
|---|---|
| Claude Haiku | 3 credits |
| Claude Sonnet | 5 credits |
| GPT-4o | 5 credits |
| Gemini 2.5 Pro | 5 credits |
| Claude Opus | BYOK only |
For BYOK users, the cost depends on the provider's per-token pricing. Claude Haiku is the cheapest at roughly $0.50–$1.00 per novel analysis. Claude Opus is the most expensive at $15–$25 per novel. The others fall in the $3–$7 range.
See our pricing page for current credit allocations by plan.
Genre-Specific Recommendations
Based on our analysis of results across genres:
Literary fiction: Claude Opus (if BYOK) or Claude Sonnet. These models handle nuance, voice, and thematic complexity best.
Romance: Claude Sonnet or GPT-4o. Both handle emotional arc tracking and genre conventions well. Sonnet is slightly better at identifying voice inconsistencies in dialogue-heavy sections.
Thriller/Mystery: GPT-4o or Claude Sonnet. Both excel at plot logic analysis and pacing assessment. GPT-4o is particularly good at identifying red herring effectiveness and twist credibility.
Fantasy/Sci-Fi: Gemini 2.5 Pro or Claude Sonnet. The large context window helps for complex worldbuilding and magic system consistency checks. Claude Sonnet offers strong character analysis for ensemble casts.
Memoir/Nonfiction: Claude Sonnet. Strong at analyzing narrative structure in nonfiction and maintaining sensitivity to personal subject matter.
Short fiction/Essays: Claude Haiku. For works under 10,000 words, the analytical depth of Haiku is sufficient, and the speed advantage makes iterative revision practical.
Our Recommendation
If you're choosing one model and want the best all-around experience: Claude Sonnet. It hits the sweet spot of analytical depth, speed, and cost for the widest range of manuscripts and genres.
If you want the absolute best analysis and have BYOK access: Claude Opus for literary fiction and complex narratives, Gemini 2.5 Pro for very long manuscripts.
If you're iterating quickly during active revision: Claude Haiku for speed, then switch to Sonnet for a deep-dive analysis when the revision stabilizes.
The Best Approach: Test and Compare
Honestly, the best way to choose is to run a chapter through two different models and compare the results. Different manuscripts respond differently to different models — your specific prose style, genre, and story structure may click better with one model than another.
Start with a free chapter analysis to see the format and depth of feedback. Then experiment with different models on your full manuscript to find the one that gives you the most useful, actionable editorial guidance.
The model is a tool. The methodology — the structured editorial pipeline that evaluates your manuscript across multiple dimensions — is what produces the value. Any model we offer will give you a professional-grade editorial report. The differences are in depth, speed, and cost at the margins.