I have used both Hudson and Jenkins. I have been following both change lists.
I still think we made the right choice by moving from Hudson to Jenkins.
The Hudson core developers are now working on Jenkins. Those who are still employed by Oracle are the ones mainly supporting Hudson (as far as I am aware the Apache Maven people are contributing fixes as well).
I’ve filed a number of bugs back in the Hudson era. I can tell you most of them were resolved in Jenkins. Many months after their resolution, the Hudson people fixed or asked for further input on those particular bugs.
The majority of the plugin developers (almost all, that is) have migrated their plugins to Jenkins and now support Jenkins mainly. In terms of plugins Jenkins is developing much, much faster. There are now some paid plugins provided by Cloudbees.
As far as I am aware, the open source community has moved in it’s majority to Jenkins.
Some companies who prefer to have paid support and don’t want the hassle of migrating to Jenkins are still using Hudson. Frankly, I don’t see why. Jenkins has commercial support too from Cloudbees, which is where Kohsuke Kawaguchi (the creator of Hudson) now works. Cloudbees now even have a free service for hosting GitHub hosted projects in their cloud. They let your OSS projects build for free! 🙂
Jenkins has improved it’s support for the cloud. As mentioned above, Cloudbees also provide this SaaS in the cloud. I am not sure if and to what extent Hudson supports this. I think they’re not so advanced at the moment; whatever the case, Hudson doesn’t provide a SaaS for the cloud, as far as I am aware.
My opinion is that if you have to pick one, it should be Jenkins.