I came across Butler when I was searching VersionTracker for something I could use to manage my bookmarks and synchronize them between my PowerBook and my iMac.
I was aware of it, but I never tried it before since I was satisfied with QuickSilver. Although it can’t synchronize my bookmarks, it turned out to be a great utility and in some ways nicer than QuickSilver. I like being able to access my bookmarks from all of my browsers anywhere, since I often switch between Camino, Firefox, and Safari. It also seems faster & less bloated than QuickSilver.
For a long time I used URL Manager Pro to manage my bookmarks, but I didn’t like having another full-blown application running all the time. I haven’t been keeping up with the latest versions, but I might give it another try.