CircleCI.

To expand on this, CircleCI lets you easily ssh into a run so you can debug it as if you were debugging it on your own machine. I cannot tell you how many times this has saved me countless hours because you don't need to wait for your changes to build and then subsequently fail repeatedly, drastically shortening the iteration cycle.

I used to use circle CI earlier. GitHub Actions was an upgrade for me.

why?

GitHub Actions, at least at that time, had a lot more coverage than circle CI.

Anda a lot more flexibility in terms of what can you do.

Drone.io

Not sure why this was downvoted/flagged, I do use Drone CI myself currently and it's quite pleasant: https://www.drone.io/

There's also the Woodpecker CI fork, which has a very similar user experience: https://woodpecker-ci.org/

When combined with Docker images, it's quite pleasant to use - you define what environment you want for the CI/CD steps, what configuration/secrets you need and define the steps (which can also just be a collection of scripts that you can run locally if need be), that's it.

Standalone, so you can integrate it with Gogs, Gitea or similar solutions for source control and perhaps a bit simpler than GitLab CI (which I also think is lovely, though maintaining on-prem GitLab isn't quite a nice experience all the time, not that you have to do that).

Will it last another 2 years? Several CI systems have come and gone.