Which tool when
There are dozens of AI tools. Most of them you don't need. Here's the shortlist — what each one is actually for, and when to reach for it.
The no-brainers
Claude
Best for: long documents, complex reasoning, writing in your voice, anything that needs nuance.
Claude handles large amounts of text better than any other tool — you can drop in a whole report, a contract, a chain of emails and it'll work with all of it. It's also the most natural to work with; less likely to give you generic, obviously-AI output.
CoWork (Claude's desktop agent) is a step further — it works inside your actual files and apps, not just in a chat window. More on that in the CoWork section.
When to use it: writing, analysis, document processing, building your AI system.
ChatGPT
Best for: quick tasks, image generation, voice mode, when you need a second opinion on Claude's output.
ChatGPT is the most widely used tool and for good reason — it's fast, versatile, and GPT-4o is genuinely excellent. Its voice mode (Advanced Voice) is the best in the market if you want a proper back-and-forth conversation. Image generation via DALL-E is also built in.
When to use it: quick lookups, image creation, voice conversations, tasks where you already have a well-tuned Custom GPT set up.
Perplexity
Best for: research with sources.
Perplexity searches the web in real time and cites everything. It's what you reach for when you need up-to-date information and want to know where it came from — market research, competitor lookups, fact-checking.
Claude and ChatGPT can also search the web, but Perplexity is built specifically for this and tends to be better at it.
When to use it: any research task where you need sources and current information.
Comparison at a glance
| Claude | ChatGPT | Perplexity | |
|---|---|---|---|
| Long documents | ✅ Best | ✓ Good | — |
| Writing quality | ✅ Best | ✓ Good | — |
| Voice mode | — | ✅ Best | — |
| Image generation | — | ✅ Yes | — |
| Real-time research | ✓ Can | ✓ Can | ✅ Best |
| Desktop agent | ✅ CoWork | — | — |
| Price | £18/mo | £18/mo | £16/mo |
The honest answer
For most of what you do at work, Claude is the right starting point. Once you've got it set up properly with your context, it'll outperform a generic ChatGPT session on almost everything.
That said, keep ChatGPT around. Some things it handles better — and there are tasks where having two different answers is useful.
Don't subscribe to both on day one. Start with Claude, get comfortable with it, and add ChatGPT later if you find you're hitting its limits.