I wish they would keep 4.1 around for a bit longer. One of the downsides of the current reasoning based training regimens is a significant decrease in creativity. And chat trained AIs were already quite "meh" at creative writing to begin with. 4.1 was the last of its breed. So we'll have to wait until "creativity" is solved. Side note: I've been wondering lately about a way to bring creativity back to these thinking…
4.1 was the best so far. With straight to the point answers, and most of the time correct. Especially for code related questions. 5.1/5.2 on their side would a lot more easily hallucinate stupid responses or stupid code snippet totally not what was expected.