I just started using iCal recently and I agree with the slowness sentiments. And this is on a 550MHz G4. Resizing the window happens at about 1 fps. I hope QE accelerates more graphic functions such as this in 10.3.
Speed aside, iCal is an absolutely brilliant program. In my opinion it's the best iApp. The interface is powerful enough to allow you to do just about everything you need to, yet it's amazingly simple and intuitive to the point where you don't have to read any manuals or tutorials to be able to understand it instantly. It's also gorgeous looking. iCal is Apple software design at its best (from a human interface point of view).
Features I'd like to see:
- Ability to stay open in the Dock when its window is closed (to show reminders etc.)
- Big speed boost
- Ability to reverse the axes in week view so that days are on the y and times are on the x
- That's about it.
(Whoops, sorry to go off topic.)