Github Actions supports heavy parallelization and fan-in/fan-out jobs just like CircleCI does, so I'm curious if there's some limitations that I haven't ran into yet. I'd go farther to say that their documentation is much richer and easier to search for.
Last time I didn't use Woodpecker for my projects/projects I was involved in (so maybe one year ago last time?), GitHub Actions were a bit harder to debug as you don't get ssh access as you get with CircleCI. Being able to just ssh into the builder/worker when something goes wrong, cuts down debugging time so much.
I've been using act[1] as a tool to develop/test actions locally, which has helped a lot for creating new actions and debugging existing ones without incurring additional build costs.
There does appear to be some solutions on the marketplace that will allow you to ssh into a runner, but I haven't had a need for them as of yet.
If folks do need to SSH into a runner to get over some humps, come and talk to me. No point in waiting to get to that 5 or 25 minute mark in a job just to change one line and have to wait again.
If folks need to SSH into a runner to debug stuff, don't talk to me nor anyone else, just chose a CI that allow you to do that without any extras nor 3rd party stuff :) CircleCI is great for that, but also Woodpecker CI ships a "run locally" command with their CLI as well, and as a huge plus, Woodpecker is 100% open source, compared to most other stuff.
I couldn't find the parallelization limits easily with GitHub. Also GA lets you build many things, one of which is CI/CD - the docs, last time I looked, suffer as a result of being less focused on CI/CD. You've obviously had a different experience. FWIW I'm currently using Actions for Portal and it's been fine, but my needs are smaller on this project compared to previously.