What do you use Hudson for?
Previously we were using cruisecontrol. We migrated because of the great failure reporting and central management that Hudson provides. Also configuring the lava lamps from a central XML feed just feels nicer, and the improving maven support is something to be excited about (order the module build order correctly - then it will be perfect
What kind of software do you build? What language is it written in?
We build search products and solutions. These are mainly written in Java.
We use maven 2. The dependency management is fantastic. If you know how to use maven effectively it saves days of effort setting up build environments, tracking down dependencies (and/or their updates) and versioning internal modules.