Other Mac OS X updates have gone more smoothly for me. Here are the problems I've noticed so far:

Safari 3 seems to have trouble with interpreting clicks, particularly from devices like the Kensington Trackball and the Wacom tablet. Unfortunately those are the only two devices I use. It will start out OK, then pages will stop responding to clicks. Text areas will show that they have been clicked on, but cannot be typed into. It almost seems as if it is misreading the mouse position, but I am not sure.

Safari also suffers from slowdowns - I imagine this has to do with Safari icon caches, so I'll have to figure out how to empty them again.

I can no longer see or mount afp shares. I can mount windows shares, but cannot see the files on them. Can no longer see or mount either firewire drive.

Update to the update! The issue with mounting afp shares turned out to be unrelated to 10.4.11. Safari's response time, particularly in form-fields remains slow.