I know that's anecdotal, but it just seems Claude is often the default.
I'm sure there are key differences in how they handle coding tasks and maybe Claude is even a little better in some areas.
However, the note I see the most from Claude users is running out of usage.
Coding differences aside, this would be the biggest factor for me using one over the other. After several months on Codex's $20/mo. plan (and some pretty significant usage days), I have only come close to my usage limit once (never fully exceeded it).
That (at least to me) seems to be a much bigger deal than coding nuances.
Open source models are available at highly competitive prices for anyone to use and are closing the gap to 6-8 months from frontier proprietary models.
There doesn't appear to be any moat.
This criticism seems very valid against advertising and social media, where strong network effects make dominant players ultra-wealthy and act like a tax, but the AI business looks terrible, and it appears that most benefits are going to accrue fairly broadly across the economy, not to a few tech titans.
NVIDIA is the one exception to that, since there is a big moat on their business, but not clear how long that will last either.