I think claude in general, writes very lazy, poor quality code, but it writes code that works in fewer iterations. This could be one of the reasons behind it's popularity - it pushes towards the end faster at all costs.

Every time codex reviews claude written rust, I can't explain it, but it almost feels like codex wants to scream at whoever wrote it.

Their latest, Qwen3.6 35B-A3B is quite capable, and fast and small enough I don't really feel constrained running it locally. Some of the others that I've run that seem reasonably good, like Gemma 4 31B and Qwen3.5 122B-A10B just feel a bit too slow, or OOM my system too often, or run up on cache limits so spend a lot of time re-processing history. But the latest Qwen3.6 is both quite strong, and lightweight enough that it feels usable on consumer hardware.

Codex is pretty good at Rust with x86 and arm intrinsics too, it replaced a bunch of hand written C/assembly code I was using. I will try Qwen and Kimi on this kind of task too.