Another data point, I definitely find Opus better for coding, but not by much. The problems I give them are generally short (<= 100 lines) and well-defined so any advantage Opus has in larger contexts won't be apparent to me. They're also generally novel problems but NOT particularly challenging (anyone with a BS CS should be able to solve them in < 1hr).

I have them working with mostly C++ and Clojure, a bit of Python, and Vimscript every once in a while. Both models are much better at Python and fairly bad at Vimscript. Clojure failure cases are mostly from invented functions and being bad at modifying existing code. I can't pick out a strong pattern in how they fail with C++, but there have been a few times where GPT4 ends up looping between the same couple unworkable solutions (maybe this indicates a poor understanding of prior context?).