Yep, definitely. I have a plus subscription, and stuff that was easy for it just a few months ago now seems to take several back-and-forths to barely approach similar results.
Science content is where I noticed the most degradation. It just stares at me using blank “it’s not in my training data” answers to questions that used to have comprehensive responses a while ago.
I think they’re scaling down the models to make them cheaper to run?