I like Jenkins.

Some criticisms of Jenkins I'm aware of (and some I share):

  * The UI is a bit ugly
  * Plugins are a minefield. Some are excellent, others are undocumented and unmaintained. The UI treats them equally so it's easy to install a bunch of bad plugins.
  * It doesn't have a good security track record.

But it's extremely popular as a self-hosted/corporate/behind the firewall solution because:

  * It's extremely flexible.
  * It can be self-administered by developers; they can get "root-like" privileges, with all configuration set from the web GUI.
  * And of course it's free software

It's easy for an admin to deploy Jenkins, set some basic authentication / security, and then let developers do whatever they want with it.