Coding Benchmark: Why I Switched from GPT-4o to Claude 3.5 for Next.js

In the fast-paced world of AI coding assistants, loyalty is a liability. I've been a die-hard OpenAI user since GPT-3, but recent projects forced me to reconsider.

I spent the last week building a complex Dashboard UI using both GPT-4o and Claude 3.5 Sonnet. The results were not just different; they were decisive.

The Test Setup

• Task: Build a "Dark Mode Responsive Data Table" with pagination and sorting.
• Stack: Next.js 14, Tailwind CSS, Shadcn UI.
• Constraint: Single prompt, no follow-up corrections allowed.

Round 1: Code Accuracy (One-Shot)

GPT-4o

GPT-4o generated a decent table. However, it hallucinated a few props on the Shadcn Table component that don't exist. It also forgot to add "use client" at the top of the file, causing a crash immediately upon saving.

• Score: 7/10
• Result: Required manual debugging.

Claude 3.5 Sonnet

Claude's output was copy-paste ready. It correctly identified that sorting requires client-side state, added the "use client" directive, and even implemented a clever utility function for the sorting logic.

• Score: 9.5/10
• Result: "It just worked."

Round 2: Context Awareness

This is where Claude truly shines. I pasted 10 different component files into the chat and asked for a refactor of the global theme provider.

GPT-4o seemed to lose track of the file structure halfway through, analyzing only the first few files deeply and offering generic advice for the rest.

Claude 3.5 Sonnet demonstrated an almost eerie understanding of the project dependency graph. It spotted a circular dependency I hadn't even noticed and suggested a fix that involved moving types to a separate types.ts file.

Round 3: Cost & Speed

While GPT-4o is incredibly fast (latency wise), the Time to Fix (TTF) makes it slower in practice.

• GPT-4o: Fast generation -> 5 minutes debugging -> 2 minutes re-prompting.
• Claude: Slower initial generation -> 0 minutes debugging.

For a developer, correctness is the ultimate speed metric.

The Verdict

If you are doing creative writing or brainstorming, GPT-4o is still king. But for engineering, refactoring, and modern web development, Claude 3.5 Sonnet is currently the undisputed champion.

It feels less like a chatbot and more like a colleague who actually reads the documentation.

Pro Tip: If you find the official API rate limits too restrictive for heavy coding sessions, consider looking into high-limit API gateways that offer specialized access tiers for developers.