Today I got around to trying CCNetConfig, which provides a UI for editing CruiseControl.NET's ccnet.config file. Thanks to the SharpDevelop project, I have a rather good test case with a couple of continuous integration plus nightly builds:
Our ccnet.config file is maintained by using Notepad (yes, you read that right). As such, I added a few <!-- --> comments here and there, mostly for pointing me to documentation, blog articles or just disabling a feature temporarily. Therefore, you can already guess my biggest gripe: on saving the file, it is auto-reformatted and all my comments are gone.
Other than that, it is a really good way of editing ccnet.config especially because all properties are easy to edit and you are presented the documentation automatically, no more searching around for tag / attribute help on the Web. Overall: very useful if you don't spend all day being release manager.