Every developer wants to know: which AI coding assistant actually performs best? Marketing claims are worthless. Benchmarks on toy problems don’t reflect real work. So I looked at what happens when these tools build the same real application from scratch.
The results challenge some popular assumptions.
The Test: A Real Task Management App
Developer Paul built the same task management dashboard using five different AI coding tools. The app included user authentication (email/password plus OAuth), CRUD operations, real-time updates, team collaboration, mobile-responsive UI, and an analytics dashboard.
The stack: Next.js 14, TypeScript, Prisma, PostgreSQL, and Tailwind CSS.
The rules: identical specifications, 8-hour time limits, empty starting directories, natural language prompting only. Each tool was measured on time-to-MVP, code quality via SonarQube, runtime bugs, and security vulnerabilities identified by Snyk.
The Results
| Tool | MVP Time | Code Quality | Runtime Bugs | Security Issues |
|---|---|---|---|---|
| Windsurf | 3h 58m | C (62/100) | 11 | 4 (2 high) |
| Cursor | 4h 23m | B (74/100) | 8 | 3 (1 high) |
| Claude Code | 5h 12m | A (86/100) | 5 | 1 (medium) |
| GitHub Copilot | 5h 56m | A (89/100) | 4 | 0 |
The fastest tool (Windsurf) shipped the most bugs. The slowest tool (Copilot) shipped zero security vulnerabilities.
What Each Tool Does Best
Cursor produced the best-looking interface and handled multi-file coordination well. Its Composer feature writes code across multiple files simultaneously - adding a delete button to the frontend and updating the API endpoint in one shot. But it left three security issues, including one rated high severity.
Claude Code delivered superior architecture and comprehensive error handling. It automatically generated documentation and achieved the highest maintainability score. This is the tool that treats your codebase like a senior engineer would - thinking about structure before rushing to output.
Windsurf was the speed demon. Fastest initial output, snappy autocomplete. But after about 30 minutes of work, the test found it “started contradicting itself.” The code had hardcoded API keys in the frontend - a significant security fail. Fast doesn’t mean production-ready.
GitHub Copilot required more prompting. Features that took one prompt with other tools required three to four prompts with Copilot. But it produced the cleanest code with zero security vulnerabilities. If you’re shipping to production, those extra prompts might be worth it.
Separate Benchmark Data Confirms the Pattern
AI Multiple’s benchmark study found similar results using a different methodology. They tested eight-step web evaluation including backend preflight, frontend rendering, login flows, and crash detection.
Results from their automated testing:
- Cursor (with Claude Opus 4.6): 0.751 combined score at $27.90 per run
- Kiro Code (with Claude Opus 4.6): 0.717 at ~$5.50
- Codex CLI (with GPT-Codex-5.2): 0.677 at ~$4.00
Their key finding: “AI code editors generate code quickly and then spend a significant portion of their runtime debugging.”
CLI tools like Claude Code cost about one-sixth as much as Cursor while delivering roughly 10 percent lower accuracy. Whether that tradeoff works depends on your budget and how much time you can spend reviewing output.
Current Pricing (March 2026)
The cost picture varies wildly depending on how you work.
GitHub Copilot
- Free: 2,000 completions + 50 premium requests/month
- Pro: $10/month
- Pro+: $39/month
- Business: $19/user/month
- Enterprise: $39/user/month
Cursor
- Free: 2,000 completions + 50 slow requests/month
- Pro: $20/month (500 fast premium requests)
- Pro+: $60/month (3x usage)
- Teams: $40/user/month
Windsurf (formerly Codeium)
- Free: 25 credits/month
- Pro: $15/month (500 credits)
- Teams: $30/user/month
Claude Code
- Consumption-based: ~$6/developer/day average
- Team seats: $150/month
- 90% of users stay under $12/day
- Heavy users: $100-200/month
For a 10-person team using tools heavily: Copilot Business runs about $2,280/year. Cursor Business hits $4,800/year. Claude Code could range from $6,000 to $18,000/year depending on usage patterns.
What This Means
Speed and quality are inversely correlated across these tools. The faster the initial output, the more time you’ll spend debugging and fixing security issues.
This makes sense. Tools optimized for instant gratification generate code before fully understanding the problem. Tools that take longer to start are modeling the codebase and considering implications.
The benchmarks suggest two categories of tool:
- Inline assistants (Copilot, Windsurf) optimize for autocomplete speed and chat during active coding
- Agentic tools (Claude Code, Cursor’s agent mode) optimize for larger refactors and autonomous task execution
Many developers now use two tools: an inline assistant for quick completions while typing, plus an agentic tool for bigger tasks and new features.
What You Should Do
For production code: GitHub Copilot’s zero security vulnerabilities matter more than its slower speed. Run everything through security scanning regardless.
For prototypes and side projects: Cursor’s balance of speed and quality makes sense when you’re not shipping to customers yet.
For cost-conscious teams: Windsurf’s $15/month Pro tier offers speed at a budget price. Just double-check everything before deployment.
For autonomous workflows: Claude Code excels when you need to describe a feature and have it figure out what files to create and modify. Its terminal-based approach works well for automation and scripting.
Don’t trust any of them blindly: These tools are “productivity multipliers, not productivity replacements.” The developer who ran these tests emphasized that effective implementation still requires experienced developers and mandatory code review.
The AI coding assistant you pick matters less than how you use it. Ship faster with the fast tools if you have rigorous review. Ship safer with the careful tools if you’re moving straight to production. Either way, you’re still responsible for what goes out the door.