I used it a while ago. I didn't notice much of any increase in speed when compared to Firefox. I didn't use it for very long though, because I didn't like it enough to keep using it, so I don't know if I would have noticed any significant speed differences had I kept using it.
No real difference noted here, either. I still have it available on the desktop, and I click on it once in a while just for grins, but no big difference over Firefox.
I use Mozilla Firefox. Never heard of Safari. Tried Google's browser, it sucked. Tried Explorer 8.0, and just like Vista, it just looks prettier, but SOS.