Funnily enough, I test code generation both on unpaid Claude and ChatGPT.

When working with Python, I've found Sonnet (pre 3.5) to be quite superior to ChatGPT (mostly 4, sometimes 3.5) with regards to verbosity, structure and prompt / instruct comprehension.

I've switched to a JavaScript project two weeks ago and the tables have turned.

Sonnet 3.5 is much more verbose and I need to make corrections a few times, whereas ChatGPTs output is shorter and on point.

I'll closely follow if this improves if Claude are focussing on JS themselves.