I choose to use Safari because it's the browser that feels the most Mac-like, has ClickToFlash and 1Password, has great H.264 video performance, has a great interface, continues to support the newest web standards, never crashes, and is already familiar to me. As long as it isn't horrendously slower than other browsers, JS performance just isn't a concern to me--it has little real effect on my day to day browsing compared to everything I just listed.