I like Cmd-[0-9] to map to my bookmarks, I like Safari Reader, I like iOS-like zoom (chrome only fakes it, and does so not very well), I like the rendered text on Safari a million times better (it's not anti-aliased on Chrome on most pages - at least that's the miserable state Chrome was till v19 I think), I like iCloud tabs and I like Safari's UI much better.

That's why I use Safari. I couldn't possibly live with Chrome even if Safari was worse that it - I absolutely hate the stupid download bar, or "Downloads/Preferences" not being standard windows but silly webpages. And don't get me started on custom contextual menus Chrome team thought were cooler than standard OS X menus (even if they were cooler, they're at least 5 times slower. So what's the point of them?)

That said, it all comes down to what your personal preferences are. The difference between browsers are not huge. Some like Safari, some like Chrome, and some like Lynx.