The workflow with delicious was not smooth. I had installed the FF addon. (Do remember it was a while ago) When you click on the delicious button a new window opens, which I don't really need and there was no way to turn it off or atleast I cudn't find one. I like the star icon in the FF address bar, one-click and done. Double-click to add tags, very intuitive and maintains the flow.

The delicious website was a drag, bad UI and navigation, just seemed too much work for just bookmarking. I really liked their social sharing features though, but that was not my priority.