Anthropic recently released Claude 4.5 Opus, and it’s changed how we use AI at our agency. Here’s the short version: Claude 4.5 Opus is best for complex analysis and strategy when you’re providing the context. Gemini 3 is best for research and retrieving information from the internet. Claude 4.5 Sonnet is best for natural writing like blog posts and social media. ChatGPT remains a solid all-rounder, though we’ve been switching most of our ChatGPT tasks over to Gemini 3.
There’s no single “best” AI model. The right choice depends entirely on what you’re trying to do.
Why We Use Claude Most Often
We use Claude more than any other AI for work. That’s because Claude has always been the best at two things: considering a large amount of context without forgetting details, and producing natural writing.
These are our primary use cases. We set up a Claude project for each of our clients and use that to build what we call a “brand ambassador.” This is an AI that has access to everything about a particular client so it can represent them accurately in the content we create.
The Token Problem (And How Opus Fixes It)
One common problem with Claude is that it frequently runs out of tokens. This happens because when you give Claude a large amount of context, it really pays attention. It considers all of that context, where other models are quicker to switch over to retrieval-augmented generation (RAG) and only pull in the information they think is relevant to the prompt.
This has always been the catch-22 with Claude. We want it to look through all the context we give it, but as a result, we’re constantly hitting that max token limit.
Claude 4.5 Opus addresses this directly. Although it’s a bigger, smarter model, it’s able to do the same task in less time, taking up less context. It also has a much bigger context window. According to Anthropic’s documentation, Claude 4.5 Opus can handle up to 200,000 tokens of input at once, and new features like prompt caching can cut redundant costs by up to 90%.
If you need to give a model a lot of context and it’s important that it pays close attention to the details, nothing beats Claude 4.5 Opus right now.
When to Use Claude 4.5 Opus
Use Opus for any task where you’re providing the context and need a large language model to do strategy, analysis, or organization.
Anthropic describes Opus 4.5 as their best model for complex, long-running tasks and agent workflows. In testing, Opus successfully handled workflows lasting hours and thousands of steps, greatly outperforming Sonnet on multi-stage reasoning tasks. It can generate entire 10-15 page plans or code modules in one pass with strong organization and consistency.
Practical examples:
- Building out a comprehensive marketing strategy
- Analyzing large documents and extracting insights
- Creating detailed project plans
- Organizing complex information across multiple sources
- Any multi-step reasoning task
When to Use Gemini 3
If you want the model to help you retrieve the context (if you need any kind of search or research across the internet), Gemini 3 is definitely the better choice.
Gemini 3 has a clear edge when it comes to web research and up-to-date information through its integration with Google Search. Its context window is massive, handling up to approximately one million tokens. This means it can ingest thousands of pages of text and retain context across long searches.
Gemini’s Deep Research feature produces well-cited, academic-style reports by querying the web. It follows a structured, pre-planned approach: generating a step-by-step research plan, finding answers, and outputting concise reports with sources. One comparison review calls it “academic-quality, in-depth” and notes it hallucinates far less thanks to real-time data access.
Practical examples:
- Researching a topic you don’t have existing materials on
- Fact-checking or verifying current information
- Building quick overviews and summaries
- Any task requiring up-to-date information from the web
When to Use Claude 4.5 Sonnet
For natural writing, Sonnet 4.5 still seems like the best option. If you’re writing a blog post, social media post, or webpage copy, Sonnet produces the most natural, engaging prose.
Anthropic notes that Sonnet excels at writing and can understand nuance and tone to generate more compelling content. In testing, Sonnet’s output shows excellent natural flow with varied sentence and paragraph lengths, smoother transitions, and a credible voice.
Claude Opus 4.5, while extremely capable, often writes with more punch and bold metaphors. That makes Opus great for brainstorming, but sometimes the tone is too consistent for final content.
A practical rule: use Sonnet for final, polished content and use Opus when you need high energy or creative brainstorming.
Practical examples for Sonnet:
- Blog posts and articles
- Social media content
- Website copy
- Newsletters
- Any content where natural voice matters
Where Does ChatGPT Fit In?
This is the honest answer: we’re not sure yet. We’re actually switching most things we used to use ChatGPT for over to Gemini 3 right now.
ChatGPT’s thinking mode and deep research mode does try a bit harder than Gemini’s. It’s more iterative, asking clarifying questions and refining its path as it researches. But it’s just not quite as smart. And ChatGPT’s search function is much less sophisticated than Gemini’s.
ChatGPT (GPT-4) remains strong at general tasks. As one guide notes, it’s a versatile tool perfect for writing emails, brainstorming ideas, and basic data analysis. Its many models and vast training give it excellent narrative skills.
The one area where ChatGPT clearly leads is coding. ChatGPT Codex is very powerful. OpenAI’s latest Codex models outperform nearly all competitors on coding benchmarks, with the GPT-5.1-Codex-Max model achieving approximately 77.9% accuracy on a large real-world coding benchmark. But that’s not something we use much in our work.
Quick Reference: Which AI for Which Task
| Task Type | Best Choice | Why |
| Complex analysis with provided context | Claude 4.5 Opus | Best at paying attention to large amounts of context |
| Web research and retrieval | Gemini 3 | Google integration and massive context window |
| Natural writing (blogs, social, copy) | Claude 4.5 Sonnet | Most natural, engaging prose |
| General tasks and brainstorming | ChatGPT or Gemini 3 | Both are versatile all-rounders |
| Coding and programming | ChatGPT Codex | Leads on coding benchmarks |
The Bottom Line
Many knowledge workers will use a combination of these tools. The key is matching the tool to the task. We use Sonnet for drafting content, Opus for deep analysis and planning, and Gemini for fact-finding and research.
The AI landscape is shifting quickly. A year ago, we were using ChatGPT for most things. Now, Claude handles most of our work tasks, with Gemini taking over research. That will probably change again. The important thing is staying flexible and using whatever tool actually produces the best results for each specific job.TJ Robertson is the founder of TJ Digital, an AI optimization agency that helps small to medium businesses show up in AI algorithms like ChatGPT and Google’s AI search results. Contact us for a free digital marketing audit of your website and current marketing efforts.