Its simpler. Installing software is as easy as dragging an image file to the Applications folder and if you want to remove it later, you just remove the icon and any resident folders to the trash - poof - its all gone. There's no registry that leaves bits and pieces behind... which makes it tough for malware writers to compromise the system. And even when you it as root, when you are asked to install new software, the application has to ask you to OK it with your master password. The interface is quite intuitive and while it takes a little getting to, you'll never feel quite the same about Windows again.
(Denny Crane: "I Don't Want To Socialize With A Pinko Liberal Democrat Commie. Say What You Like About Republicans. We Stick To Our Convictions. Even When We Know We're Dead Wrong.")