It's not the most powerful one. It's not the free one. Here's why.
If you're using GitHub Copilot with a premium subscription in Visual Studio 2026, you already know the model choice matters. After spending a lot of time coding C# and .NET 10 with Copilot — roughly six hours a day — here's where I've landed.
Full video: My Go to Model for GitHub Copilot
Anthropic Models Are a Solid Starting Point
When it comes to code quality, models from Anthropic — like Claude Haiku and Claude Sonnet — are a consistently strong choice. They tend to generate cleaner code with fewer bugs and usually require less manual rework than many alternatives.
It genuinely feels like Anthropic has made software development a primary focus when training their models. That said, this isn't about dismissing other models — it's about what's been working well in my day-to-day workflow.
The Free Models Have One Big Problem
The free models are technically capable. For occasional use, they're fine.
But their biggest drawback is speed.
In a separate video where I compare model performance in Visual Studio 2026, even for very simple tasks, the free models were roughly two to three times slower than premium alternatives. That might sound tolerable, but compounded across a full coding session, it constantly interrupts your flow.
There's no real benefit in using AI if the productivity gain is minimal. The tool should accelerate your work — not make you wait.
Agent Mode: Where Premium Really Pays Off
With a GitHub Copilot premium subscription, you also get access to agent mode in Visual Studio. This allows you to use multiple models to perform more human-like tasks: creating new solutions and projects, generating files, doing code reviews, and more.
A common example is a full codebase rewrite — where you need AI to create a new solution, add multiple projects, install NuGet packages, and wire up project references. On a large codebase, this should happen fast. With free models, it often takes far too long, and sometimes struggles just to generate a basic shell solution with empty projects.
Sure, you can do all of this manually for small solutions. But at scale, speed matters.
Why I Default to Claude Haiku 4.5
If I had to choose only one model for day-to-day coding, it would be Claude Haiku 4.5. For my typical work, it's good enough about 80% of the time.
The cost difference is significant: Haiku costs roughly one-third of a Claude Sonnet 4.5. When I use higher-end premium models for around six hours of coding a day, I typically burn through my entire monthly premium request quota within 10 to 15 days. Haiku stretches that budget considerably further.
Using the more powerful premium models for routine tasks — scaffolding, boilerplate, test generation — is often overkill. These tasks don't require deep reasoning. They require speed and accuracy. There are many everyday development tasks where speed matters more than raw intelligence.
The Switching Strategy
I also have a separate video on switching between free and premium models as a cost-saving strategy, but the short version is this:
|
Task Type |
My Go-To Model |
|---|---|
|
Boilerplate, scaffolding, tests |
Claude Haiku 4.5 |
|
Complex logic, architecture |
Claude Sonnet 4.5 |
|
When Haiku gets stuck |
Step up one tier |
Haiku is my default baseline. I only switch to more powerful options when Haiku gets stuck, or the task truly demands it.
The Bottom Line
Claude Haiku 4.5 hits the right balance between cost and performance for everyday coding. It's fast, affordable, and handles the majority of real-world development tasks well.
Start with Haiku. Escalate when you need to. Your workflow — and your monthly quota — will thank you.
Full Video
https://youtu.be/Dqf1Pt2alY0?embedable=true
Tagged: GitHub Copilot, Visual Studio 2026, Claude AI, Anthropic, C#, .NET 10, AI Developer Tools, Copilot Premium