I'm now running Leopard. After backing up my drive, Tiger upgraded flawlessly. I still have to decide if I like certain things, but they are pretty cool-looking. I'm not liking the icon preview being on by default. When browsing a directory of avi files it kicks the fans in.
Spaces is a little strange when I switch between applications. Say I have a Safari window open in space 1 and another in space 2. I'm working in another application in space 2 and I command-tab back to Safari. Instead of going to the Safari window in the current space it will whisk you to the desktop of the first Safari window. Kind of annoying and I can't seem to find a setting to adjust that.
They got rid of the old calendar widget and confused me really bad because they replaced it with the iCal widget, which looks the same, but will now show iCal events.
We'll see how things go. Time to do a clean install on my mini and bask in the new Front Row.