Ask HN: Professional devs, what has been your experience using Codex/Co-pilot?

I haven't had a chance to use either of these tools yet, but I'm interested to learn from those who have. All I see are articles and tweets saying how amazing they both are, but I haven't really heard updates from software development professionals about how well (or not) this is working for them on a daily basis. What has your experience been like? How has it impacted your workflow? Is this a fad or will it have staying power in your opinion?