How we tested
Marketing pages make every writing assistant sound identical: faster drafts, better tone, fewer typos. To separate them, we gave each tool the same five tasks. A difficult customer email that needed to apologise without admitting liability. A 1,200-word explainer on heat pumps for a general audience. A dense internal report that needed cutting by forty percent. A cover letter rewritten in a warmer voice. And a set of three blog headlines with a strict character limit.
We scored every output on accuracy, structure, tone control, the amount of editing it needed afterwards, and how well the tool followed explicit instructions. We also read each provider's data policy, because pasting a confidential report into a chatbot is a decision with consequences.
The general-purpose assistants
Claude (Anthropic) — best for long drafts and careful editing
Claude was the most dependable at following detailed briefs. When we asked it to cut the report by forty percent while keeping every figure, it did exactly that and listed what it removed. Its long context window means you can paste an entire document and ask for consistent changes throughout. It occasionally errs on the side of caution, but for professional writing that is rarely a problem.
ChatGPT (OpenAI) — the most versatile all-rounder
ChatGPT handled every task competently and was the fastest at producing varied options. Its headline suggestions were the strongest in the test, and custom instructions make it easy to set a house style once and reuse it. The free tier is generous enough for occasional writing. Its weakness is a tendency to add confident filler, so read drafts closely before publishing.
Gemini (Google) — best if you live in Google Workspace
Gemini's raw drafting was slightly behind the two leaders, but its integration with Google Docs and Gmail is a real advantage. Drafting a reply inside Gmail with the thread already in context saves the copy-and-paste step entirely. If your team already pays for Workspace, try it before adding another subscription.
The editing specialists
Grammarly — best for everyday correctness
Grammarly is less of a drafting tool and more of a second pair of eyes that follows you across your browser, email client and word processor. Its tone detector is genuinely useful for spotting emails that read colder than intended. The generative features are improving, but the core value remains catching mistakes as you type.
LanguageTool — the best free and multilingual option
LanguageTool supports more than twenty languages and its free browser extension catches most grammar and punctuation errors. For writers working in English and another European language, it is the clear choice. Privacy-conscious teams also appreciate that a self-hosted server version exists.
Jasper — built for marketing teams
Jasper wraps a capable model in marketing-specific features: brand voice profiles, campaign templates and team collaboration. For a solo writer it is expensive compared with a general assistant, but agencies juggling several brand voices will find the structure worthwhile.
| Tool | Drafting | Editing | Free tier | Best for |
|---|---|---|---|---|
| Claude | Excellent | Excellent | Yes, limited | Long-form, reports |
| ChatGPT | Excellent | Very good | Yes | All-round use |
| Gemini | Very good | Good | Yes | Google Workspace users |
| Grammarly | Fair | Excellent | Yes | Everyday correctness |
| LanguageTool | Basic | Very good | Yes | Multilingual writers |
| Jasper | Very good | Good | Trial only | Marketing teams |
How to get better results from any assistant
The biggest improvement in our tests came not from switching tools but from writing better briefs. State the audience, the purpose, the length and one example of the tone you want. Ask for an outline first, approve it, then request the draft. And always ask the assistant to flag any facts it is unsure about; most will do so honestly when prompted.