I've been using Opus 5.5 for pretty much everything
I tried giving Astra a shot. Since it scores better on math, I thought it might do better at writing Lean. I forgot the exact details, but that didn't end up being the case. I think it wasn't thinking holistically enough and tended to rabbit hole itself more
Same experience on my vibe coding side project. Astra seems autistic to the context, Claude seems more of an open minded partner with good taste.
Opus 5.5 is a god tier model, but for serious large scale work, nothing beats getting at least three non-similar models to repeatedly refine a super detailed plan before any code is written.
Right now my consortium is Opus 5.5, Grok 4.7 and Muse Wonder. These three are different enough that their insights are very complementary. Once a plan is detailed enough, any decent model can execute on it successfully, but I personally like Grok’s ability to stick to the plan. (And no 5-hour quota!)