I have just tested icloud in Leopard. Followed instructions on this site and got it to work. Then deleted the icloud account as I am not ready to make the jump.
Now I have multiple calendar entries. This is a biggy for me. My calendard is VIP for my business; planning and a long term record of what I have done. I am a long term Apple user. Had a few issues with other phones in the past, then iphone came along and it was all fixed.
Now Apple is pushing users to the cloud and the simple cable sync is not working. This is a fundemental break down of trust. If I can not plug an iphone into a mac and get seemless integration of items like calendar then the products are not worth the price tag. THE key featre of Apple has always been that it just works. And no the cloud is not the answer. I do ot want to be forced into storing everything in the cloud. Apple, you are turning into Micrsoft. Can't trust you any more!