One thing on codex I've noticed.. and I could be wrong.. but sometimes it just seems to use a lower model without telling you. Its very obvious when it happens because the replies it gives and the code it creates are pure garbage.
I've been using codex high. It does great for small stuff, but kinda goes really crazy with large tasks. I wanted to add some new api hooks for other devs and it created like 20 classes lol. Claude did it in 3
For me its speed. I'm a big speed optimization guy. I cant stand code that is not tuned to be highly optimized. And it gets very frustrating having to go and clean up various things. Its crazy but its one of my OCD things I just cannot help. Started in colledge with a parallel processing class, you got extra points for who's ever code ran the fastest.
When you are dealing with a GOM that has 50k objects in it and you are are operating OOP, you cant just say hey lets loop through the entire GOM to grab this item, or whatever.