I just wanted some opinions from people that have run Selenium (http://selenium.openqa.org) I have had a lot of experience with WaTiN and even wrote a recording suite for it. I
I'm a big fan of Selenium. One major gotcha that's good to know about ahead of time, though, is that Selenium IDE has a lot of trouble with pop-up windows. These problems don't persist in Selenium RC, but it can make development a bit of a headache.