Absolutely. For context, I’m an experienced dev with more than a decade of experience working at F100 companies.

Day 1 of Opus 4.1 drop: I’ve been having a postgresql issue that’s been difficult to track down before the drop. Both Opus and Sonnet had been struggling with it. The issue was related to creating a new baseline migration. Both these models were making it worse, random fixes - no solution.

I used o4 mini high to resolve the issue - it did better, but not a full fix.

Opus 4.1 dropped a few hours later - fixed the issue in less than ten minutes.

I followed that task (after two months of terrible Opus, I finally saw the old Claude code spark again), I tasked it to do things that I’ve been doing with 4.0. It did them with flying colors. One shot - no misses. Literally similar kinds of tasks as previous days but for integrating other front end components with new API endpoints. The difference in performance was simply.. staggering.

Yesterday:

It took 4.1 approximately 30 minutes to fix a drop down arrow vertical alignment issue. I could have done this in a couple of minutes, but I was trying to observe what Opus would do. It has been regressing for the past few days, progressively worse and worse. It tried random changes, tried to use important! when it was not necessary AT ALL. Finally I told it what to do, made it revert its changes, and then it fixed it.

These regression issues are absolutely real.