I had been using Safari since I bought my Mac. But Safari is a pure browser with no extension capabilities and I was really missing some of the extensions I had got used to on Firefox, such as ScrapBook, WebDeveloper, FireFTP, FlashGot or Gmail Notifier. So I downloaded Firefox for my Mac and switched back. One interesting side effect is that Firefox appears significantly faster at downloading and displaying pages. Don't get me wrong, Safari is a great browser, but I find Firefox better.