I'm also warming to the idea of treating CI as "pipelines", and find myself thinking of tooling more in that way.
I love the integrated CI, though, and the use cases it enables. I love that I can just make a pipeline that lints, tests and compiles my code and then, if all of those pass, ends with deploying it to production.
There are many more Gitlab features I like a lot, and the fact that they're all integrated is icing on the cake.
For everything else, I like Gitlab a lot -- it seems to have the best integration of tools of any code host.