Leopard really is a serious improvement, if your hardware can handle it.
As for Safari, well. I like the rendering and the speed, I actively don't want anti-phishing things and you've got to laugh at that Microsoft "security risk" - "oh Safari might download stuff to the desktop which Windows autoruns, clearly Safari's fault". I switch between default browsers on a regular basis, Camino, Firefox, Opera, Safari, but I can't say that's making any difference to me at all.