Finally, installed Tiger on my main partition. First impressions:

Not much changed from a daily-use perspective. Spotlight could be very useful some times for finding “lost” files(although I use QuickSilver still much more, but you can't really compare them anyway), Dashboard is quite a gimmick currently, but Automator rocks. It has some issues in the UI here,

so there's space for improvements, but in general pretty cool and certainly useful. With the ecto actions, I can for example select some pictures in the Finder, automatically resize them and upload them to a blog. With just one click ;) And all I have to do to set that up is drag'n'drop some actions from one window to the other. Grrrrreat