Leap Into Leopard?

I’ve been using OSX “Leopard” for some time now. My review: meh. There are some things that run faster and I like the data detector. The UI “improvements” are actually downgrades in most cases: e.g file icons try to “preview” even at 32 pixels on the desktop so any useful information, like the application with which the file will open (preview? acrobat?) is lost and the missing dock in ical makes editing events a many-click process. There are stability issues in some applications (Safari, which never crashed under 10.4, has crashed repeatedly in the last month). What drives me most insane are little quirks like: all of my calendar events disappear (sometimes to reappear) when I add a new item (an apple-z/undo takes care of the situation, but then I have to edit the event again). My favorite: in the window bar of mail.app (or when I’m in exposé and I mouse over mail, see picture) the program informs me that I have 4.3 BILLION messages in my inbox. Now that’s a lot of email!