Everyone has opinions about AI coding tools. Very few have data.
I got tired of the "Cursor is best" / "No, Claude Code is best" / "Actually Windsurf..." debates, so I did something stupid: I built the exact same application five times, with five different tools, and measured everything.
Here's what I learned.
The Experiment
The App: A task management dashboard with:
- User authentication (email/password + OAuth)
- CRUD operations for tasks
- Real-time updates
- Team collaboration features
- Mobile-responsive UI
- Basic analytics dashboard
The Stack: Next.js 14, TypeScript, Prisma, PostgreSQL, Tailwind CSS
The Rules:
- Same spec document for all tools
- Same 8-hour time limit
- Same starting point (empty directory)
- No manual coding except for config files
- All prompting done in natural language
What I Measured:
- Time to working MVP
- Lines of code generated
- TypeScript errors on first compile
- Runtime bugs found in testing
- Code quality score (SonarQube)
- Security vulnerabilities (Snyk)
Let's get into it.
Tool #1: Cursor (Composer Mode)
Version tested: Cursor 0.43 with Claude 3.5 Sonnet
Cursor has been the darling of AI coding for the past year, and for good reason. Composer mode, where it can edit multiple files simultaneously is genuinely magical when it works.
The Build Experience
I started with: "Create a Next.js 14 task management app with authentication, real-time updates, and team collaboration."
Cursor's first response? A complete project scaffold with:
- App Router structure
- Prisma schema
- Auth setup (NextAuth)
- Basic CRUD API routes
- A surprisingly nice UI
Time to first working page: 12 minutes
I was impressed. Then I started testing.
Where It Shined
- UI generation: Cursor produced the best-looking interface of all five tools. The Tailwind usage was clean and consistent.
- File coordination: When I asked for a new feature, it correctly updated the schema, API routes, and frontend together.
- Error recovery: When I pointed out bugs, it usually fixed them on the first try.
Where It Struggled
- Authentication edge cases: The initial OAuth setup worked, but session handling had gaps. Tokens weren't refreshing correctly.
- Real-time features: It defaulted to polling instead of WebSockets, even when I specifically asked for real-time.
- Database migrations: Generated migrations that worked locally but failed in production due to column ordering issues.
The Numbers
| Metric | Result |
|---|---|
| Time to MVP | 4h 23m |
| Lines of Code | 3,847 |
| TypeScript Errors (first compile) | 12 |
| Runtime Bugs Found | 8 |
| SonarQube Score | B (74/100) |
| Security Issues | 3 (1 high, 2 medium) |
The high-severity security issue: An exposed API route that didn't check authentication. Oops.
Tool #2: Claude Code (CLI)
Version tested: Claude Code 1.0.23 with Claude 3.5 Sonnet
Claude Code is Anthropic's terminal-based coding agent. It's less visual than Cursor but more autonomous, you can tell it to "build X" and walk away.
The Build Experience
Same starting prompt. Very different approach.
Claude Code asked clarifying questions first:
- "Should I use the App Router or Pages Router?"
- "Do you want email/password auth, OAuth, or both?"
- "Real-time via WebSockets or Server-Sent Events?"
This took an extra 10 minutes upfront but saved me hours later.
Time to first working page: 27 minutes
Slower start, but the foundation was solid.
Where It Shined
- Architecture: Claude Code's generated code was the most maintainable of all five. Clear separation of concerns, consistent patterns.
- Error handling: It actually included try/catch blocks and meaningful error messages. Revolutionary, I know.
- Documentation: It generated JSDoc comments and a README without being asked.
Where It Struggled
- UI polish: The interface was functional but ugly. Tailwind usage was inconsistent.
- Speed: Being terminal-based, the feedback loop was slower. No instant previews.
- Complex refactors: When I asked it to restructure the authentication system, it got confused about which files it had already modified.
The Numbers
| Metric | Result |
|---|---|
| Time to MVP | 5h 12m |
| Lines of Code | 4,231 |
| TypeScript Errors (first compile) | 4 |
| Runtime Bugs Found | 5 |
| SonarQube Score | A (86/100) |
| Security Issues | 1 (medium) |
Highest code quality of the bunch. Slowest to pretty, though.
Tool #3: Windsurf (by Codeium)
Version tested: Windsurf 1.2.1
Windsurf markets itself as having "flows" persistent context that remembers your entire project history. In theory, this solves the "AI forgets what it did yesterday" problem.
The Build Experience
Windsurf's onboarding was slick. It analyzed my project type and suggested a tech stack before I asked.
The "flow" concept worked... sometimes. When I asked for a feature, it referenced code it had written earlier. When I asked to modify that feature, it often forgot the context entirely.
Time to first working page: 18 minutes
Where It Shined
- Speed: Windsurf was the fastest at generating initial code. The autocomplete is snappy.
- Explanations: Every code block came with comments explaining what it did and why.
- IDE integration: The VS Code-like interface felt familiar and polished.
Where It Struggled
- Consistency: The "flows" weren't as persistent as advertised. After ~30 minutes of work, it started contradicting itself.
- Complex logic: Business logic for team permissions was a mess. It generated five different permission-checking approaches across the codebase.
- Testing: When I asked for tests, it generated tests for the wrong components.
The Numbers
| Metric | Result |
|---|---|
| Time to MVP | 3h 58m |
| Lines of Code | 3,612 |
| TypeScript Errors (first compile) | 18 |
| Runtime Bugs Found | 11 |
| SonarQube Score | C (62/100) |
| Security Issues | 4 (2 high, 2 medium) |
Fastest to "working," but "working" is generous here. The security issues included hardcoded API keys in the frontend. 😬
Tool #4: Replit Agent
Version tested: Replit Agent (December 2025)
Replit Agent is different. It's not just a coding assistant, it's an autonomous agent that deploys your app too. Tell it what you want, and it builds, tests, and ships.
The Build Experience
The promise: "Describe your app, then go get coffee."
The reality: "Describe your app, watch it work for 20 minutes, realize it went down the wrong path, start over."
Replit Agent made bold decisions without asking. It chose a completely different database (MongoDB instead of PostgreSQL), implemented auth differently than I specified, and styled everything with its own CSS instead of Tailwind.
Time to first working page: 34 minutes
But it was deployed and live. That's something.
Where It Shined
- End-to-end: No other tool gave me a deployed, publicly accessible app this fast.
- Infrastructure: Database provisioning, environment variables, deployment all handled automatically.
- Iteration speed: Once it understood the project, small changes were instant.
Where It Struggled
- Control: I felt like a passenger. When it made wrong decisions, correcting them was harder than starting fresh.
- Performance: The generated code was not optimized. Pages that should load in 200ms took 2+ seconds.
- Vendor lock-in: The generated code was tightly coupled to Replit's infrastructure. Moving it elsewhere would require significant refactoring.
The Numbers
| Metric | Result |
|---|---|
| Time to MVP | 4h 47m |
| Lines of Code | 2,891 |
| TypeScript Errors (first compile) | 7 |
| Runtime Bugs Found | 9 |
| SonarQube Score | C (58/100) |
| Security Issues | 2 (1 high, 1 medium) |
Best for prototypes you'll throw away. Worst for production code you'll maintain.
Tool #5: GitHub Copilot (Agent Mode)
Version tested: Copilot Agent in VS Code (January 2026)
GitHub Copilot has been around longest, but Agent Mode, where it can execute multi-step plans is relatively new.
The Build Experience
Copilot Agent felt like the most "professional" option. Less magic, more predictable. It generated code incrementally, asking for confirmation at each step.
Time to first working page: 22 minutes
Where It Shined
- Predictability: I always knew what it was doing and why. No surprises.
- Integration: GitHub integration was seamless. It understood my existing workflow.
- Testing: Generated the most comprehensive test suite of all five tools.
Where It Struggled
- Ambition: It was conservative. Features I got in one prompt with other tools took 3-4 with Copilot.
- Modern patterns: It defaulted to older Next.js patterns. Took explicit prompting to use App Router features.
- Speed: The slowest at raw code generation. It thinks before it types.
The Numbers
| Metric | Result |
|---|---|
| Time to MVP | 5h 56m |
| Lines of Code | 4,456 |
| TypeScript Errors (first compile) | 2 |
| Runtime Bugs Found | 4 |
| SonarQube Score | A (89/100) |
| Security Issues | 0 |
Slowest to MVP. Best quality. Zero security issues.
The Final Comparison
| Tool | Time to MVP | Code Quality | Bugs | Security Issues | Best For |
|---|---|---|---|---|---|
| Cursor | 4h 23m | B (74) | 8 | 3 | Fast iteration, nice UI |
| Claude Code | 5h 12m | A (86) | 5 | 1 | Maintainable production code |
| Windsurf | 3h 58m | C (62) | 11 | 4 | Quick prototypes |
| Replit Agent | 4h 47m | C (58) | 9 | 2 | Deployed demos |
| GitHub Copilot | 5h 56m | A (89) | 4 | 0 | Production-ready enterprise code |
My Honest Recommendations
For Side Projects & Experiments
Winner: Cursor
The UI generation is unmatched. The speed is great. The code quality issues don't matter if you're building something to learn or demo.
For Production Code You'll Maintain
Winner: GitHub Copilot (Agent Mode)
Yes, it's slower. Yes, it's less flashy. But zero security issues and the highest code quality score mean fewer 3 AM debugging sessions.
Runner-up: Claude Code
If you can live with the terminal interface, Claude Code's architectural decisions are consistently excellent. The code reads like a senior developer wrote it.
For Rapid Prototyping
Winner: Windsurf
If you need something to show investors tomorrow and don't care about technical debt, Windsurf will get you there fastest.
For Non-Developers / "Vibe Coding"
Winner: Replit Agent
If you genuinely don't want to touch code and just want a deployed app, Replit Agent is the only tool that delivers end-to-end without you opening a terminal.
What I'd Actually Use
Here's my honest setup going into 2026:
- GitHub Copilot for production work at my day job
- Cursor for side projects and UI-heavy features
- Claude Code for complex refactoring and architectural decisions
I don't use a single tool for everything. The best results come from knowing each tool's strengths and picking accordingly.
The Uncomfortable Truth
All five tools produced code with bugs. All of them made architectural decisions I wouldn't have made. All of them required human review and correction.
The hype says AI coding tools will replace developers. The reality is they make experienced developers faster and inexperienced developers dangerous.
These tools are productivity multipliers, not productivity replacements. A 10x engineer with AI becomes a 20x engineer. A 0.1x engineer with AI is still 0.1x, just with more code to debug.
Choose your tools wisely. And always, always review what they generate.
Which AI coding tool are you using? Did these results surprise you? Let me know in the comments.
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