The biggest argument against Hudson is that every release introduces new bugs.
Releases are very frequent, so you have to upgrade frequently so you don't fall behind. That means that you need to devote a lot of time to diagnosing issues and rolling back to previous Hudson releases. (Sometimes a rollback isn't even possible!)
We are introducing Continuous Deployment in our shop (when you check in code, it gets deployed on the live site!) and having to wrestle with Hudson is costing us too much.
We are actively looking at migrating to TeamCity purely because of the cost of Hudson's bugs.
