I don't doubt Opus is technically superior, but it's not practically superior for me.

It's still pretty much impossible to have any LLM one-shot a complex implementation. There's just too many details to figure out and too much to explain for it to get correct. Often, there's uncertainty and ambiguity that I only understand the correct answer (or rather less bad answer) after I've spent time deep in the code. Having Opus spit out a possibly correct solution just isn't useful to me. I need to understand _why_ we got to that solution and _why_ it's a correct solution for the context I'm working in.

For me, this means that I largely have an iteratively driven implementation approach where any particular task just isn't that complex. Therefore, Sonnet is completely sufficient for my day-to-day needs.