Before buying a Mac mini in 2005, the last time, I had used an Apple product was when I started the computer lab at my high school with a couple of used Apple IIs (1983). The school let me do it because I had "experience" programming Commodore VIC-20s and Commodore 64s. LOL.
I am happy to say I am back to loving computers again after buying that Mac mini ( and a MacBook in 2006 ). I tossed Firefox off my Mac after one too many crashes and recently tried Safari. I was much impressed with the speed. I decided that speed and stability are more important to me than extensibility ( in a browser ).
Don't get me wrong, I like Firefox. I really do. But sometimes it feels slow and kludgey. It takes a long time to start up, consumes a lot of system resources, and crashes on me for no apparent reason.
Safari isn't without it's faults ( lack of an extension mechanism is one of them ) but it doesn't crash nearly as often, and it's very responsive. If my tests with the development version of WebKit is any indication of what to expect in Safari (WebKit is FRACKING FAST!), then Firefox is about to leave my desktop for a long time.