It's the only secure browser, its fast, and the UI is really great (having saved sessions, and all bookmarks downloads, history in the same place). The share function is SUPER handy with handoff (although I imagine such functions will be replaced by timeline etc).
I used to use opera, chrome. At one point firefox. Now I am kind of annoyed having to use another browser if I use another PC.
I discovered yesterday that the pdf reading function is much quicker than any other apps I've tried for pdfs.
Yeah I like it.
Only downside really is that some web developers don't follow the html5 standards properly. (Like this site for example, there are a few glitches that show its developed outside the standard). If people could actually follow the standards it'd be prefect.