Why is Mac OS X better than Windows 8.1?

I'm definitely considering a mac, I just wanted to know some pros/cons of the OS. I currently own a thickish, one-year old Toshiba Satellite 14" model with a touch screen, an Ivy Bridge i5, and 6gb of RAM. I want to get the new MB Air 13". I'm pretty happy with my current laptop. I'd say it's still about a 7-8/10 in performance overall. I also own a Surface RT that I use almost exclusively for taking back and forth to school to take notes and how. I figured an Air would do the jobs of both, being a reliable work horse at home, and a portable grab-and-go device. I'm just on the fence about switching to OS X. I have little experience with it. So tell me, Verge, what are some pros 'n cons of OS X?