For me personally? yes absoluttly.

Opus 5 vs. 5.5 is a clear stepup.

Problem is, you need to do a diverse set of experiments to recognize it. Blender support got relevant better,t he amount of corrections got less etc.

It does very much vary with the domain though. I haven't personally noticed much improvement, they're still useful but unreliable, in my view the idea of agents, harnesses etc has been a distraction and functions to cover up the lack of progress in the underlying models.

But everyone has a different view of this, it'll be interesting to see how it plays out.