I have had similar questions, and am still evaluating here. However, I've been increasingly frustrated with the sheer volume of anecdotal evidence from yay and naysayers of LLM-assisted coding. I have personally felt increased productivity at times with it, and frustrations at others.

In order to better research, I built (ironically, mostly vibe coded) a tool to run structured "self-experiments" on my own usage of AI. The idea is I've init a bunch of hypotheses I have around my own productivity/fulfillment/results with AI-assisted coding. The tool lets me establish those then run "blocks" where I test a particular strategy for a time period (default 2 weeks). So for example, I might have a "no AI" block followed by a "some AI" block followed by a "full agent all-in AI block".

The tool is there to make doing check-ins easier, basically a tiny CLI wrapper around journaling that stays out of my way. It also does some static analysis on commit frequency, code produced, etc. but I haven't fleshed out that part of it much and have been doing manual analysis at the end of blocks.

For me this kind of self-tracking has been more helpful than hearsay, since I can directly point to periods where it was working well and try to figure out why or what I was working on. It's not fool-proof, obviously, but for me the intentionality has helped me get clearer answers.

Whether those results translate beyond a single engineer isn't a question I'm interested in answering and feels like a variant of developer metrics-black-hole, but maybe we'll get more rigorous experiments in time.

The tool open source here (may be bugs, only been using it a few weeks): https://github.com/wellwright-labs/devex