OK, i decided to do some data collection after jmjanzen's last comment. I wanted to see if webkit made my bookmarks load faster. In my observation it seemed to render them a lot faster, but I wanted to check it out with a simple test. So i started with microb/gecko and loaded each of my bookmarks one at a time, closing the browser after each instance (i will call this a cold start). Then for my second test I went through them with the browser already open to see how much of it was the browser starting up (warm start). Then I did the same with Webkit enabled. Here is what I found. All observations are in seconds

webpage gecko (cold/warm) Webkit (cold/warm)

dealnews.com 50/40 55/50
reddit.com 15/10 17/10
maemo.org 20/12 17/12
engadget.com 50/45 28/21
wikipedia.org 12/8 12/8
internettablettalk.com 30/20 25/22
maps.google.com 55/45 35/26

I was a little shocked at the results. Webkit seemed so much faster in my day to day use. Maybe I was going to engadget and other javascript heavy pages more than my bookmarks, as it does seem to make a difference there.