Jenkins is not perfect by any means, but I can say it is much better than existing solutions (taking pros and cons after trying and using many of them). Sure, it doesn't have fancy UI or flying buttons, nor is it rust/PWA/react/whatever-rage-is-these-days, but it does its job - it works, is free, and has been very well-maintained for ages. Download a single file and run it. Want to extend it? There is a plugin for everything under the sun (but be careful, you can easily bloat it).
IMHO, I don't want bells and whistles from the CI tool. CI tools are dry; I see them as a car drive shaft - it must work properly, and I don't expect it to be pretty. If you need to showcase it, you are probably doing something wrong.
And one more thing: I expect Jenkins to be around and free in the next 10 years. I doubt that will be the case for "insert-your-favorite-ci-from-some-company".
IMHO, I don't want bells and whistles from the CI tool. CI tools are dry; I see them as a car drive shaft - it must work properly, and I don't expect it to be pretty. If you need to showcase it, you are probably doing something wrong.
And one more thing: I expect Jenkins to be around and free in the next 10 years. I doubt that will be the case for "insert-your-favorite-ci-from-some-company".