I've been using all three of these for real work over the past couple months. Not toy projects. Actual production code across a Node.js backend, React frontend, and some Python scripts. Here's an honest comparison.

GitHub Copilot: The Best Autocomplete Ever Made

Copilot lives in your editor. That's its biggest advantage. There's zero context switching. You type a comment or start a function and it suggests the next chunk of code inline. Accept with Tab, reject by typing something else. Friction is near zero.

Where it shines: repetitive patterns, boilerplate, test scaffolding, and anything where the intent is obvious from context. If I'm writing a series of similar API route handlers, Copilot nails the pattern after the first one. It reads my file and understands what I'm building.

Where it struggles: complex logic that requires understanding the broader system. It can't see your whole codebase, just the current file and maybe a few open tabs. So when the solution depends on how another service works or a database schema in a different file, Copilot guesses. And it guesses wrong often enough that you learn to be cautious.

Cost: $10/month. Worth every penny. I accept probably 30-40% of its suggestions, and each one saves me a few seconds to a few minutes of typing.

ChatGPT: The Problem-Solving Partner

ChatGPT is a different tool entirely. You don't use it while you're typing code. You use it when you're stuck, when you're planning, or when you need to understand something. It's a conversation, not an autocomplete.

Where it shines: debugging, architecture discussions, learning new libraries, writing complex functions where you need to think through the approach first. I paste in error messages, describe what I'm trying to build, or ask it to compare different approaches. The conversational nature means I can iterate. "That's close, but the constraint is X" and it adjusts.

Where it struggles: it doesn't have your codebase context (unless you paste it in), it hallucinates APIs that don't exist, and its training data cuts off so recent library versions are a blind spot. I've learned to always verify what it tells me about specific library methods.

Cost: free tier is usable but slow. ChatGPT Plus at $20/month gets you faster responses and GPT-4 access. I pay for Plus and use it daily.

Tabnine: The Third Wheel

I wanted to like Tabnine. I really did. It was one of the early AI coding assistants and it has a privacy-focused approach where it can run models locally. That's genuinely appealing if you work with sensitive code.

But honestly, after using Copilot, Tabnine's suggestions feel a step behind. The completions are shorter, less context-aware, and less often useful. Where Copilot suggests entire function bodies, Tabnine tends to suggest the next line or two. It's good autocomplete, but Copilot is great autocomplete.

The local model option is slower and less accurate than the cloud version. And the cloud version, well, at that point the privacy advantage is gone and you're paying for an inferior Copilot.

I cancelled my Tabnine subscription after three weeks. If privacy is your primary concern, it's a valid choice. For everyone else, Copilot is just better.

How I Use Them Together

My actual workflow uses Copilot and ChatGPT together. They serve different purposes and barely overlap.

Copilot handles the micro-level: line-by-line coding, boilerplate, patterns. It reduces the typing. ChatGPT handles the macro-level: planning, debugging, understanding. It reduces the thinking (or more accurately, it accelerates the thinking).

A typical session looks like this: I describe a feature to ChatGPT and discuss the approach. Once I've got a plan, I open my editor and start coding with Copilot handling the boilerplate. When I hit a bug I can't quickly figure out, I paste the relevant code into ChatGPT and talk through it.

Together they probably save me 1-2 hours a day. That's not a precise measurement, just a gut feeling after months of use. But the quality of the time changes too. Less time on tedious typing and Stack Overflow searching. More time on the interesting problems.

The Bottom Line

If you can only pick one, pick ChatGPT. It's more versatile and the free tier is good enough to start. If you can afford both, get Copilot too. The combination is greater than the sum of its parts. Skip Tabnine unless you specifically need local/private AI completion.

We're early in this space. These tools are going to get dramatically better in the next year. But even in their current state, not using them feels like choosing to write code without syntax highlighting. You can do it, but why would you?