I just don't like Chrome, for one. But, I really like the scrolling, pinch to zoom, swipe to go backwards, bookmark syncing across my multiple computers, etc.
I prefer Safari because it integrates into the Apple ecosystem, including e.g. iCloud tabs, Keychain integration, gesture support; because it's a native application; because it's perfectly performant; because it doesn't phone home. I don't write web applications or even use many, so my needs are well satisfied.
It blows the other browsers away in scrolling performance on a retina display laptop. Chrome has gotten a lot better recently, but it's still worse enough that it's worth putting up with Safari's weaknesses.
- iClouds tab sync
- quite fast
- two-finger swipe for back/forward with nice "cover" effect
- scrolling is silky smooth*
- iCloud keychain*
* available on Mavericks. Scrolling was good enough earlier, but on Mavericks its butter smooth.