On May 31, 2008 I gave a presenation at RailsConf titled The Great Test Framework Dance-off. Here are the slides from that talk.
These slides are made available under Creative Commons license Attribution-Noncommercial 3.0 Unported. That means you can do what you want with them as long as you don't make money off it and give me credit for my work.
The slides: The Great Test Framework Dance-off