Yeah, I see these takes a lot. A bunch of people saying e.g. they use DeepSeek 4.1 flash for all their coding and notice no difference to frontier models

I tried it for a day running everything twice, once with opus 5.5 and once with deepseek. If you notice no difference... I don't know what to say.

I think maybe it's people working on tiny self contained things where code quality doesn't matter that much? But in a big codebase, the open models just aren't good enough to make good changes