GPT-4o, o3, Sonnet, Opus, Gemini Pro — Which AI Model Should You Use? The 2026 Complete Selection Guide

Thu, 14 May 2026 17:00:00 +0900

“Wait — what’s the difference between ChatGPT’s o3 and GPT-4o?”

A colleague asked me this the other day, and I couldn’t answer on the spot. “It’s the smarter one” doesn’t cut it as an explanation.

AI is evolving so fast that each company now offers multiple models simultaneously. OpenAI has GPT-4o, o3, and GPT-4o mini running in parallel. Anthropic lines up Sonnet, Opus, and Haiku. Google splits between Flash and Pro. Before you can even “use AI,” you’re stuck deciding which model to use.

AI Model Comparison on firebirdテックトーク

GPT-4o, o3, Sonnet, Opus, Gemini Pro — Which AI Model Should You Use? The 2026 Complete Selection Guide