Last i heard was that developers FELT

Several of those studies were published on early 2025 data, LLM agents have been rapidly improving since then. In early 2025 I would agree with the sentiment - it was kind of equivocal for overall productiveness. By early 2026 I'd say it was a much clearer advantage, both in doing the same kind of work faster, but more importantly: in doing better work at the same speed or even a little faster.