Out of interest who here uses Selenium or any other for of testing for the client side of web apps, such as JSUnit?

At my company we use it to test a .NET web app written in C# and using the ExtJS framework. It's a very useful tool.

Someone at my workplace has been throwing together some tests with Watir recently and overall things look good, but we're yet to take it past the experiment-on-his-desktop stage.