I have been using the WebKit nightly and it flies. I have never zipped around the web so fast. It is insane! Not only that, but with my normal selection of apps running, much less CPU time is being used. As soon as I open up the non-webkit Safari more CPU time is taken up just having it running in the background with some tabs open. I have not compared memory usage, so that is something I will have to do next. The speed improvements are absolutely mind boggling though.