I've used Jenkins in a few places, right back from when it was Hudson. Back then I was amazed at the concept of CI in general so it was pretty great.

Over the years I've worked with most of the major players, most recently Gitlab CI. The one thing that makes it hard to go back to Jenkins is the poor quality of the plugin ecosystem. So many are abandoned or buggy that any upgrade comes with a breath and a prayer.

I'm probably gone for good. Appreciate everything they did for the industry but there are more robust choices around.