Just wanted to throw this out there for anyone who has an older MPB and is worried about slow downs with newer OS. Mavericks seems to be greatly optimized even for older systems. I remember going from Snow Leopard to Lion and it was horrible. I upgraded to Mavericks GM and it's very smooth and so far the battery life has been at least as good as Snow Leopard.
Scrolling and animations within the OS are also superb. I believe this has to do with the new openGL implementation.
Scrolling and animations within the OS are also superb. I believe this has to do with the new openGL implementation.