I mean I don't use it or ChatGPT, but it's clearly the leader based on what others what done with it. It's also kind of implied that if several Chinese labs do some degree of distillation of Claude, then they think Opus is the best.
Normally here for learning, but I use claude on a regular basis for a project. It is really good. I've built something that would have taken 20 engineers six months or more prior to the "AI" era. Scoping, design, algorithms, tests, documentation, and even compliance. I've been careful and had external fleshy reviewers just to be careful. Claude's been very, very good.
PS. I pay for it.