CI is just the thing no one wants to deal with, yet everyone wants to just work. And like any code or process, you need engineering to make it good. And like any project, you can't just blame bad tools for crappy results.
The thing I want to change are things that I do in the build system so that it is checked in and previous versions when we need to build them (we are embedded where field failure is expensive so there are typically branches for the current release, next release, and head). This also means anything that can fail on CI can fail on my local system (unless it depends on something like the number of cores on the machine running the build).
While the details can be slightly different, how we have CI is how it should be. most developers should have better things to do than worry about how to configure CI.
Whereas, I could articulate why I didn't like Jenkins just fine :)
(I don't recall _loving_ it, though I don't have as many bad memories of it as I do for VSTS/TFS, GitLab, GH Actions, Jenkins Groovyfiles, ...)
We needed two more or less completely different configurations for old a new versions of the same software (think hotfix for past releases), but TeamCity can't handle this scenario at all. So now we have duplicated the configuration and some hacky version checks that cancel incompatible builds.
Maybe their new Pipeline stuff fixes some of these short comings.
This is making me realize I want a CI with as few features as possible. If I'm going to spend months of my life debugging this thing I want as few corners to check as I can manage.
I tend to stick with the GUI because if you're doing JVM style work the complexity and tasks is all in the build you can run locally, the CI system is more about task scheduling so it's not that hard to configure. But being able to migrate from GUI to code when the setup becomes complex enough to justify it is a very nice thing.
I swear by TeamCity. It doesn't seem to have any of these problems other people are facing with GitHub Actions. You can configure it with a GUI, or in XML, or using a type safe Kotlin DSL. These all actually interact so you can 'patch' a config via the GUI even if the system is configured via code, and TeamCity knows how to store config in a git repository and make commits when changes are made, which is great for quick things where it's not worth looking up the DSL docs or for experimentation.
The UI is clean and intuitive. It has all the features you'd need. It scales. It isn't riddled with insecure patterns like GH Actions is.