I have just switched and slowly adjusting to Mac OS X. I really like Safari, it does almost all that I need and looks great, however there is one problem. Being a Mozilla user for a long time I really like this feature when you right-click on a link and in the pop-up menu choose "Save link target as..". This allows you to specify the location as well as the name of the file. Surprisingly, Safari only lets you download in one location and you cannot change the name of the file until it's downloaded. Or maybe this is possible, I am just doing something wrong?
I often look for publications on the web and save them in different folders. I also use the name of the paper as the filename. So this is really important to me. Of course I can use Mozilla in parallel, but I would rather be consistent with my browser (you know, bookmarks, etc.)