1. THIS IS A BIG DEAL (especially if you're still deciding between ChatGPT and Claude)
GPT-5.4 isn't just "ChatGPT got smarter."
It's a complete redesign of what ChatGPT can actually do.
Before, you'd type a question, get an answer, and that was it.
Now? It can actually control your computer, manage your files, browse the web, and complete multi-step tasks without you babysitting it.
Let me break down the 6 biggest changes in plain English in the comments :)